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putty/ssh2connection-server.c

305 строки
9.1 KiB
C
Исходник Обычный вид История

Add an actual SSH server program. This server is NOT SECURE! If anyone is reading this commit message, DO NOT DEPLOY IT IN A HOSTILE-FACING ENVIRONMENT! Its purpose is to speak the server end of everything PuTTY speaks on the client side, so that I can test that I haven't broken PuTTY when I reorganise its code, even things like RSA key exchange or chained auth methods which it's hard to find a server that speaks at all. (For this reason, it's declared with [UT] in the Recipe file, so that it falls into the same category as programs like testbn, which won't be installed by 'make install'.) Working title is 'Uppity', partly for 'Universal PuTTY Protocol Interaction Test Yoke', but mostly because it looks quite like the word 'PuTTY' with part of it reversed. (Apparently 'test yoke' is a very rarely used term meaning something not altogether unlike 'test harness', which is a bit of a stretch, but it'll do.) It doesn't actually _support_ everything I want yet. At the moment, it's a proof of concept only. But it has most of the machinery present, and the parts it's missing - such as chained auth methods - should be easy enough to add because I've built in the required flexibility, in the form of an AuthPolicy object which can request them if it wants to. However, the current AuthPolicy object is entirely trivial, and will let in any user with the password "weasel". (Another way in which this is not a production-ready server is that it also has no interaction with the OS's authentication system. In particular, it will not only let in any user with the same password, but it won't even change uid - it will open shells and forwardings under whatever user id you started it up as.) Currently, the program can only speak the SSH protocol on its standard I/O channels (using the new FdSocket facility), so if you want it to listen on a network port, you'll have to run it from some kind of separate listening program similar to inetd. For my own tests, I'm not even doing that: I'm just having PuTTY spawn it as a local proxy process, which also conveniently eliminates the risk of anyone hostile connecting to it. The bulk of the actual code reorganisation is already done by previous commits, so this change is _mostly_ just dropping in a new set of server-specific source files alongside the client-specific ones I created recently. The remaining changes in the shared SSH code are numerous, but all minor: - a few extra parameters to BPP and PPL constructors (e.g. 'are you in server mode?'), and pass both sets of SSH-1 protocol flags from the login to the connection layer - in server mode, unconditionally send our version string _before_ waiting for the remote one - a new hook in the SSH-1 BPP to handle enabling compression in server mode, where the message exchange works the other way round - new code in the SSH-2 BPP to do _deferred_ compression the other way round (the non-deferred version is still nicely symmetric) - in the SSH-2 transport layer, some adjustments to do key derivation either way round (swapping round the identifying letters in the various hash preimages, and making sure to list the KEXINITs in the right order) - also in the SSH-2 transport layer, an if statement that controls whether we send SERVICE_REQUEST and wait for SERVICE_ACCEPT, or vice versa - new ConnectionLayer methods for opening outgoing channels for X and agent forwardings - new functions in portfwd.c to establish listening sockets suitable for remote-to-local port forwarding (i.e. not under the direction of a Conf the way it's done on the client side).
2018-10-21 00:09:54 +03:00
/*
* Server-specific parts of the SSH-2 connection layer.
*/
#include <assert.h>
#include "putty.h"
#include "ssh.h"
#include "sshbpp.h"
#include "sshppl.h"
#include "sshchan.h"
#include "sshcr.h"
#include "ssh2connection.h"
#include "sshserver.h"
Add an SFTP server to the SSH server code. Unlike the traditional Unix SSH server organisation, the SFTP server is built into the same process as all the rest of the code. sesschan.c spots a subsystem request for "sftp", and responds to it by instantiating an SftpServer object and swapping out its own vtable for one that talks to it. (I rather like the idea of an object swapping its own vtable for a different one in the middle of its lifetime! This is one of those tricks that would be absurdly hard to implement in a 'proper' OO language, but when you're doing vtables by hand in C, it's no more difficult than any other piece of ordinary pointer manipulation. As long as the methods in both vtables expect the same physical structure layout, it doesn't cause a problem.) The SftpServer object doesn't deal directly with SFTP packet formats; it implements the SFTP server logic in a more abstract way, by having a vtable method for each SFTP request type with an appropriate parameter list. It sends its replies by calling methods in another vtable called SftpReplyBuilder, which in the normal case will write an SFTP reply packet to send back to the client. So SftpServer can focus more or less completely on the details of a particular filesystem API - and hence, the implementation I've got lives in the unix source directory, and works directly with file descriptors and struct stat and the like. (One purpose of this abstraction layer is that I may well want to write a second dummy implementation, for test-suite purposes, with completely controllable behaviour, and now I have a handy place to plug it in in place of the live filesystem.) In between sesschan's parsing of the byte stream into SFTP packets and the SftpServer object, there's a layer in the new file sftpserver.c which does the actual packet decoding and encoding: each request packet is passed to that, which pulls the fields out of the request packet and calls the appropriate method of SftpServer. It also provides the default SftpReplyBuilder which makes the output packet. I've moved some code out of the previous SFTP client implementation - basic packet construction code, and in particular the BinarySink/ BinarySource marshalling fuinction for fxp_attrs - into sftpcommon.c, so that the two directions can share as much as possible.
2018-10-21 00:10:32 +03:00
void ssh2connection_server_configure(
PacketProtocolLayer *ppl, const SftpServerVtable *sftpserver_vt)
{
struct ssh2_connection_state *s =
container_of(ppl, struct ssh2_connection_state, ppl);
s->sftpserver_vt = sftpserver_vt;
}
Add an actual SSH server program. This server is NOT SECURE! If anyone is reading this commit message, DO NOT DEPLOY IT IN A HOSTILE-FACING ENVIRONMENT! Its purpose is to speak the server end of everything PuTTY speaks on the client side, so that I can test that I haven't broken PuTTY when I reorganise its code, even things like RSA key exchange or chained auth methods which it's hard to find a server that speaks at all. (For this reason, it's declared with [UT] in the Recipe file, so that it falls into the same category as programs like testbn, which won't be installed by 'make install'.) Working title is 'Uppity', partly for 'Universal PuTTY Protocol Interaction Test Yoke', but mostly because it looks quite like the word 'PuTTY' with part of it reversed. (Apparently 'test yoke' is a very rarely used term meaning something not altogether unlike 'test harness', which is a bit of a stretch, but it'll do.) It doesn't actually _support_ everything I want yet. At the moment, it's a proof of concept only. But it has most of the machinery present, and the parts it's missing - such as chained auth methods - should be easy enough to add because I've built in the required flexibility, in the form of an AuthPolicy object which can request them if it wants to. However, the current AuthPolicy object is entirely trivial, and will let in any user with the password "weasel". (Another way in which this is not a production-ready server is that it also has no interaction with the OS's authentication system. In particular, it will not only let in any user with the same password, but it won't even change uid - it will open shells and forwardings under whatever user id you started it up as.) Currently, the program can only speak the SSH protocol on its standard I/O channels (using the new FdSocket facility), so if you want it to listen on a network port, you'll have to run it from some kind of separate listening program similar to inetd. For my own tests, I'm not even doing that: I'm just having PuTTY spawn it as a local proxy process, which also conveniently eliminates the risk of anyone hostile connecting to it. The bulk of the actual code reorganisation is already done by previous commits, so this change is _mostly_ just dropping in a new set of server-specific source files alongside the client-specific ones I created recently. The remaining changes in the shared SSH code are numerous, but all minor: - a few extra parameters to BPP and PPL constructors (e.g. 'are you in server mode?'), and pass both sets of SSH-1 protocol flags from the login to the connection layer - in server mode, unconditionally send our version string _before_ waiting for the remote one - a new hook in the SSH-1 BPP to handle enabling compression in server mode, where the message exchange works the other way round - new code in the SSH-2 BPP to do _deferred_ compression the other way round (the non-deferred version is still nicely symmetric) - in the SSH-2 transport layer, some adjustments to do key derivation either way round (swapping round the identifying letters in the various hash preimages, and making sure to list the KEXINITs in the right order) - also in the SSH-2 transport layer, an if statement that controls whether we send SERVICE_REQUEST and wait for SERVICE_ACCEPT, or vice versa - new ConnectionLayer methods for opening outgoing channels for X and agent forwardings - new functions in portfwd.c to establish listening sockets suitable for remote-to-local port forwarding (i.e. not under the direction of a Conf the way it's done on the client side).
2018-10-21 00:09:54 +03:00
static ChanopenResult chan_open_session(
struct ssh2_connection_state *s, SshChannel *sc)
{
PacketProtocolLayer *ppl = &s->ppl; /* for ppl_logevent */
Start using C99 variadic macros. In the past, I've had a lot of macros which you call with double parentheses, along the lines of debug(("format string", params)), so that the inner parens protect the commas and permit the macro to treat the whole printf-style argument list as one macro argument. That's all very well, but it's a bit inconvenient (it doesn't leave you any way to implement such a macro by prepending another argument to the list), and now this code base's rules allow C99isms, I can switch all those macros to using a single pair of parens, using the C99 ability to say '...' in the parameter list of the #define and get at the corresponding suffix of the arguments as __VA_ARGS__. So I'm doing it. I've made the following printf-style macros variadic: bpp_logevent, ppl_logevent, ppl_printf and debug. While I'm here, I've also fixed up a collection of conditioned-out calls to debug() in the Windows front end which were clearly expecting a macro with a different calling syntax, because they had an integer parameter first. If I ever have a need to condition those back in, they should actually work now.
2018-12-08 23:32:31 +03:00
ppl_logevent("Opened session channel");
Add an SFTP server to the SSH server code. Unlike the traditional Unix SSH server organisation, the SFTP server is built into the same process as all the rest of the code. sesschan.c spots a subsystem request for "sftp", and responds to it by instantiating an SftpServer object and swapping out its own vtable for one that talks to it. (I rather like the idea of an object swapping its own vtable for a different one in the middle of its lifetime! This is one of those tricks that would be absurdly hard to implement in a 'proper' OO language, but when you're doing vtables by hand in C, it's no more difficult than any other piece of ordinary pointer manipulation. As long as the methods in both vtables expect the same physical structure layout, it doesn't cause a problem.) The SftpServer object doesn't deal directly with SFTP packet formats; it implements the SFTP server logic in a more abstract way, by having a vtable method for each SFTP request type with an appropriate parameter list. It sends its replies by calling methods in another vtable called SftpReplyBuilder, which in the normal case will write an SFTP reply packet to send back to the client. So SftpServer can focus more or less completely on the details of a particular filesystem API - and hence, the implementation I've got lives in the unix source directory, and works directly with file descriptors and struct stat and the like. (One purpose of this abstraction layer is that I may well want to write a second dummy implementation, for test-suite purposes, with completely controllable behaviour, and now I have a handy place to plug it in in place of the live filesystem.) In between sesschan's parsing of the byte stream into SFTP packets and the SftpServer object, there's a layer in the new file sftpserver.c which does the actual packet decoding and encoding: each request packet is passed to that, which pulls the fields out of the request packet and calls the appropriate method of SftpServer. It also provides the default SftpReplyBuilder which makes the output packet. I've moved some code out of the previous SFTP client implementation - basic packet construction code, and in particular the BinarySink/ BinarySource marshalling fuinction for fxp_attrs - into sftpcommon.c, so that the two directions can share as much as possible.
2018-10-21 00:10:32 +03:00
CHANOPEN_RETURN_SUCCESS(sesschan_new(sc, s->ppl.logctx,
s->sftpserver_vt));
Add an actual SSH server program. This server is NOT SECURE! If anyone is reading this commit message, DO NOT DEPLOY IT IN A HOSTILE-FACING ENVIRONMENT! Its purpose is to speak the server end of everything PuTTY speaks on the client side, so that I can test that I haven't broken PuTTY when I reorganise its code, even things like RSA key exchange or chained auth methods which it's hard to find a server that speaks at all. (For this reason, it's declared with [UT] in the Recipe file, so that it falls into the same category as programs like testbn, which won't be installed by 'make install'.) Working title is 'Uppity', partly for 'Universal PuTTY Protocol Interaction Test Yoke', but mostly because it looks quite like the word 'PuTTY' with part of it reversed. (Apparently 'test yoke' is a very rarely used term meaning something not altogether unlike 'test harness', which is a bit of a stretch, but it'll do.) It doesn't actually _support_ everything I want yet. At the moment, it's a proof of concept only. But it has most of the machinery present, and the parts it's missing - such as chained auth methods - should be easy enough to add because I've built in the required flexibility, in the form of an AuthPolicy object which can request them if it wants to. However, the current AuthPolicy object is entirely trivial, and will let in any user with the password "weasel". (Another way in which this is not a production-ready server is that it also has no interaction with the OS's authentication system. In particular, it will not only let in any user with the same password, but it won't even change uid - it will open shells and forwardings under whatever user id you started it up as.) Currently, the program can only speak the SSH protocol on its standard I/O channels (using the new FdSocket facility), so if you want it to listen on a network port, you'll have to run it from some kind of separate listening program similar to inetd. For my own tests, I'm not even doing that: I'm just having PuTTY spawn it as a local proxy process, which also conveniently eliminates the risk of anyone hostile connecting to it. The bulk of the actual code reorganisation is already done by previous commits, so this change is _mostly_ just dropping in a new set of server-specific source files alongside the client-specific ones I created recently. The remaining changes in the shared SSH code are numerous, but all minor: - a few extra parameters to BPP and PPL constructors (e.g. 'are you in server mode?'), and pass both sets of SSH-1 protocol flags from the login to the connection layer - in server mode, unconditionally send our version string _before_ waiting for the remote one - a new hook in the SSH-1 BPP to handle enabling compression in server mode, where the message exchange works the other way round - new code in the SSH-2 BPP to do _deferred_ compression the other way round (the non-deferred version is still nicely symmetric) - in the SSH-2 transport layer, some adjustments to do key derivation either way round (swapping round the identifying letters in the various hash preimages, and making sure to list the KEXINITs in the right order) - also in the SSH-2 transport layer, an if statement that controls whether we send SERVICE_REQUEST and wait for SERVICE_ACCEPT, or vice versa - new ConnectionLayer methods for opening outgoing channels for X and agent forwardings - new functions in portfwd.c to establish listening sockets suitable for remote-to-local port forwarding (i.e. not under the direction of a Conf the way it's done on the client side).
2018-10-21 00:09:54 +03:00
}
static ChanopenResult chan_open_direct_tcpip(
struct ssh2_connection_state *s, SshChannel *sc,
ptrlen dstaddr, int dstport, ptrlen peeraddr, int peerport)
{
PacketProtocolLayer *ppl = &s->ppl; /* for ppl_logevent */
Channel *ch;
char *dstaddr_str, *err;
dstaddr_str = mkstr(dstaddr);
Start using C99 variadic macros. In the past, I've had a lot of macros which you call with double parentheses, along the lines of debug(("format string", params)), so that the inner parens protect the commas and permit the macro to treat the whole printf-style argument list as one macro argument. That's all very well, but it's a bit inconvenient (it doesn't leave you any way to implement such a macro by prepending another argument to the list), and now this code base's rules allow C99isms, I can switch all those macros to using a single pair of parens, using the C99 ability to say '...' in the parameter list of the #define and get at the corresponding suffix of the arguments as __VA_ARGS__. So I'm doing it. I've made the following printf-style macros variadic: bpp_logevent, ppl_logevent, ppl_printf and debug. While I'm here, I've also fixed up a collection of conditioned-out calls to debug() in the Windows front end which were clearly expecting a macro with a different calling syntax, because they had an integer parameter first. If I ever have a need to condition those back in, they should actually work now.
2018-12-08 23:32:31 +03:00
ppl_logevent("Received request to connect to port %s:%d (from %.*s:%d)",
dstaddr_str, dstport, PTRLEN_PRINTF(peeraddr), peerport);
Add an actual SSH server program. This server is NOT SECURE! If anyone is reading this commit message, DO NOT DEPLOY IT IN A HOSTILE-FACING ENVIRONMENT! Its purpose is to speak the server end of everything PuTTY speaks on the client side, so that I can test that I haven't broken PuTTY when I reorganise its code, even things like RSA key exchange or chained auth methods which it's hard to find a server that speaks at all. (For this reason, it's declared with [UT] in the Recipe file, so that it falls into the same category as programs like testbn, which won't be installed by 'make install'.) Working title is 'Uppity', partly for 'Universal PuTTY Protocol Interaction Test Yoke', but mostly because it looks quite like the word 'PuTTY' with part of it reversed. (Apparently 'test yoke' is a very rarely used term meaning something not altogether unlike 'test harness', which is a bit of a stretch, but it'll do.) It doesn't actually _support_ everything I want yet. At the moment, it's a proof of concept only. But it has most of the machinery present, and the parts it's missing - such as chained auth methods - should be easy enough to add because I've built in the required flexibility, in the form of an AuthPolicy object which can request them if it wants to. However, the current AuthPolicy object is entirely trivial, and will let in any user with the password "weasel". (Another way in which this is not a production-ready server is that it also has no interaction with the OS's authentication system. In particular, it will not only let in any user with the same password, but it won't even change uid - it will open shells and forwardings under whatever user id you started it up as.) Currently, the program can only speak the SSH protocol on its standard I/O channels (using the new FdSocket facility), so if you want it to listen on a network port, you'll have to run it from some kind of separate listening program similar to inetd. For my own tests, I'm not even doing that: I'm just having PuTTY spawn it as a local proxy process, which also conveniently eliminates the risk of anyone hostile connecting to it. The bulk of the actual code reorganisation is already done by previous commits, so this change is _mostly_ just dropping in a new set of server-specific source files alongside the client-specific ones I created recently. The remaining changes in the shared SSH code are numerous, but all minor: - a few extra parameters to BPP and PPL constructors (e.g. 'are you in server mode?'), and pass both sets of SSH-1 protocol flags from the login to the connection layer - in server mode, unconditionally send our version string _before_ waiting for the remote one - a new hook in the SSH-1 BPP to handle enabling compression in server mode, where the message exchange works the other way round - new code in the SSH-2 BPP to do _deferred_ compression the other way round (the non-deferred version is still nicely symmetric) - in the SSH-2 transport layer, some adjustments to do key derivation either way round (swapping round the identifying letters in the various hash preimages, and making sure to list the KEXINITs in the right order) - also in the SSH-2 transport layer, an if statement that controls whether we send SERVICE_REQUEST and wait for SERVICE_ACCEPT, or vice versa - new ConnectionLayer methods for opening outgoing channels for X and agent forwardings - new functions in portfwd.c to establish listening sockets suitable for remote-to-local port forwarding (i.e. not under the direction of a Conf the way it's done on the client side).
2018-10-21 00:09:54 +03:00
err = portfwdmgr_connect(
s->portfwdmgr, &ch, dstaddr_str, dstport, sc, ADDRTYPE_UNSPEC);
sfree(dstaddr_str);
if (err != NULL) {
Start using C99 variadic macros. In the past, I've had a lot of macros which you call with double parentheses, along the lines of debug(("format string", params)), so that the inner parens protect the commas and permit the macro to treat the whole printf-style argument list as one macro argument. That's all very well, but it's a bit inconvenient (it doesn't leave you any way to implement such a macro by prepending another argument to the list), and now this code base's rules allow C99isms, I can switch all those macros to using a single pair of parens, using the C99 ability to say '...' in the parameter list of the #define and get at the corresponding suffix of the arguments as __VA_ARGS__. So I'm doing it. I've made the following printf-style macros variadic: bpp_logevent, ppl_logevent, ppl_printf and debug. While I'm here, I've also fixed up a collection of conditioned-out calls to debug() in the Windows front end which were clearly expecting a macro with a different calling syntax, because they had an integer parameter first. If I ever have a need to condition those back in, they should actually work now.
2018-12-08 23:32:31 +03:00
ppl_logevent("Port open failed: %s", err);
Add an actual SSH server program. This server is NOT SECURE! If anyone is reading this commit message, DO NOT DEPLOY IT IN A HOSTILE-FACING ENVIRONMENT! Its purpose is to speak the server end of everything PuTTY speaks on the client side, so that I can test that I haven't broken PuTTY when I reorganise its code, even things like RSA key exchange or chained auth methods which it's hard to find a server that speaks at all. (For this reason, it's declared with [UT] in the Recipe file, so that it falls into the same category as programs like testbn, which won't be installed by 'make install'.) Working title is 'Uppity', partly for 'Universal PuTTY Protocol Interaction Test Yoke', but mostly because it looks quite like the word 'PuTTY' with part of it reversed. (Apparently 'test yoke' is a very rarely used term meaning something not altogether unlike 'test harness', which is a bit of a stretch, but it'll do.) It doesn't actually _support_ everything I want yet. At the moment, it's a proof of concept only. But it has most of the machinery present, and the parts it's missing - such as chained auth methods - should be easy enough to add because I've built in the required flexibility, in the form of an AuthPolicy object which can request them if it wants to. However, the current AuthPolicy object is entirely trivial, and will let in any user with the password "weasel". (Another way in which this is not a production-ready server is that it also has no interaction with the OS's authentication system. In particular, it will not only let in any user with the same password, but it won't even change uid - it will open shells and forwardings under whatever user id you started it up as.) Currently, the program can only speak the SSH protocol on its standard I/O channels (using the new FdSocket facility), so if you want it to listen on a network port, you'll have to run it from some kind of separate listening program similar to inetd. For my own tests, I'm not even doing that: I'm just having PuTTY spawn it as a local proxy process, which also conveniently eliminates the risk of anyone hostile connecting to it. The bulk of the actual code reorganisation is already done by previous commits, so this change is _mostly_ just dropping in a new set of server-specific source files alongside the client-specific ones I created recently. The remaining changes in the shared SSH code are numerous, but all minor: - a few extra parameters to BPP and PPL constructors (e.g. 'are you in server mode?'), and pass both sets of SSH-1 protocol flags from the login to the connection layer - in server mode, unconditionally send our version string _before_ waiting for the remote one - a new hook in the SSH-1 BPP to handle enabling compression in server mode, where the message exchange works the other way round - new code in the SSH-2 BPP to do _deferred_ compression the other way round (the non-deferred version is still nicely symmetric) - in the SSH-2 transport layer, some adjustments to do key derivation either way round (swapping round the identifying letters in the various hash preimages, and making sure to list the KEXINITs in the right order) - also in the SSH-2 transport layer, an if statement that controls whether we send SERVICE_REQUEST and wait for SERVICE_ACCEPT, or vice versa - new ConnectionLayer methods for opening outgoing channels for X and agent forwardings - new functions in portfwd.c to establish listening sockets suitable for remote-to-local port forwarding (i.e. not under the direction of a Conf the way it's done on the client side).
2018-10-21 00:09:54 +03:00
sfree(err);
CHANOPEN_RETURN_FAILURE(
SSH2_OPEN_CONNECT_FAILED, ("Connection failed"));
}
Start using C99 variadic macros. In the past, I've had a lot of macros which you call with double parentheses, along the lines of debug(("format string", params)), so that the inner parens protect the commas and permit the macro to treat the whole printf-style argument list as one macro argument. That's all very well, but it's a bit inconvenient (it doesn't leave you any way to implement such a macro by prepending another argument to the list), and now this code base's rules allow C99isms, I can switch all those macros to using a single pair of parens, using the C99 ability to say '...' in the parameter list of the #define and get at the corresponding suffix of the arguments as __VA_ARGS__. So I'm doing it. I've made the following printf-style macros variadic: bpp_logevent, ppl_logevent, ppl_printf and debug. While I'm here, I've also fixed up a collection of conditioned-out calls to debug() in the Windows front end which were clearly expecting a macro with a different calling syntax, because they had an integer parameter first. If I ever have a need to condition those back in, they should actually work now.
2018-12-08 23:32:31 +03:00
ppl_logevent("Port opened successfully");
Add an actual SSH server program. This server is NOT SECURE! If anyone is reading this commit message, DO NOT DEPLOY IT IN A HOSTILE-FACING ENVIRONMENT! Its purpose is to speak the server end of everything PuTTY speaks on the client side, so that I can test that I haven't broken PuTTY when I reorganise its code, even things like RSA key exchange or chained auth methods which it's hard to find a server that speaks at all. (For this reason, it's declared with [UT] in the Recipe file, so that it falls into the same category as programs like testbn, which won't be installed by 'make install'.) Working title is 'Uppity', partly for 'Universal PuTTY Protocol Interaction Test Yoke', but mostly because it looks quite like the word 'PuTTY' with part of it reversed. (Apparently 'test yoke' is a very rarely used term meaning something not altogether unlike 'test harness', which is a bit of a stretch, but it'll do.) It doesn't actually _support_ everything I want yet. At the moment, it's a proof of concept only. But it has most of the machinery present, and the parts it's missing - such as chained auth methods - should be easy enough to add because I've built in the required flexibility, in the form of an AuthPolicy object which can request them if it wants to. However, the current AuthPolicy object is entirely trivial, and will let in any user with the password "weasel". (Another way in which this is not a production-ready server is that it also has no interaction with the OS's authentication system. In particular, it will not only let in any user with the same password, but it won't even change uid - it will open shells and forwardings under whatever user id you started it up as.) Currently, the program can only speak the SSH protocol on its standard I/O channels (using the new FdSocket facility), so if you want it to listen on a network port, you'll have to run it from some kind of separate listening program similar to inetd. For my own tests, I'm not even doing that: I'm just having PuTTY spawn it as a local proxy process, which also conveniently eliminates the risk of anyone hostile connecting to it. The bulk of the actual code reorganisation is already done by previous commits, so this change is _mostly_ just dropping in a new set of server-specific source files alongside the client-specific ones I created recently. The remaining changes in the shared SSH code are numerous, but all minor: - a few extra parameters to BPP and PPL constructors (e.g. 'are you in server mode?'), and pass both sets of SSH-1 protocol flags from the login to the connection layer - in server mode, unconditionally send our version string _before_ waiting for the remote one - a new hook in the SSH-1 BPP to handle enabling compression in server mode, where the message exchange works the other way round - new code in the SSH-2 BPP to do _deferred_ compression the other way round (the non-deferred version is still nicely symmetric) - in the SSH-2 transport layer, some adjustments to do key derivation either way round (swapping round the identifying letters in the various hash preimages, and making sure to list the KEXINITs in the right order) - also in the SSH-2 transport layer, an if statement that controls whether we send SERVICE_REQUEST and wait for SERVICE_ACCEPT, or vice versa - new ConnectionLayer methods for opening outgoing channels for X and agent forwardings - new functions in portfwd.c to establish listening sockets suitable for remote-to-local port forwarding (i.e. not under the direction of a Conf the way it's done on the client side).
2018-10-21 00:09:54 +03:00
CHANOPEN_RETURN_SUCCESS(ch);
}
ChanopenResult ssh2_connection_parse_channel_open(
struct ssh2_connection_state *s, ptrlen type,
PktIn *pktin, SshChannel *sc)
{
if (ptrlen_eq_string(type, "session")) {
return chan_open_session(s, sc);
} else if (ptrlen_eq_string(type, "direct-tcpip")) {
ptrlen dstaddr = get_string(pktin);
int dstport = toint(get_uint32(pktin));
ptrlen peeraddr = get_string(pktin);
int peerport = toint(get_uint32(pktin));
return chan_open_direct_tcpip(
s, sc, dstaddr, dstport, peeraddr, peerport);
} else {
CHANOPEN_RETURN_FAILURE(
SSH2_OPEN_UNKNOWN_CHANNEL_TYPE,
("Unsupported channel type requested"));
}
}
Convert a lot of 'int' variables to 'bool'. My normal habit these days, in new code, is to treat int and bool as _almost_ completely separate types. I'm still willing to use C's implicit test for zero on an integer (e.g. 'if (!blob.len)' is fine, no need to spell it out as blob.len != 0), but generally, if a variable is going to be conceptually a boolean, I like to declare it bool and assign to it using 'true' or 'false' rather than 0 or 1. PuTTY is an exception, because it predates the C99 bool, and I've stuck to its existing coding style even when adding new code to it. But it's been annoying me more and more, so now that I've decided C99 bool is an acceptable thing to require from our toolchain in the first place, here's a quite thorough trawl through the source doing 'boolification'. Many variables and function parameters are now typed as bool rather than int; many assignments of 0 or 1 to those variables are now spelled 'true' or 'false'. I managed this thorough conversion with the help of a custom clang plugin that I wrote to trawl the AST and apply heuristics to point out where things might want changing. So I've even managed to do a decent job on parts of the code I haven't looked at in years! To make the plugin's work easier, I pushed platform front ends generally in the direction of using standard 'bool' in preference to platform-specific boolean types like Windows BOOL or GTK's gboolean; I've left the platform booleans in places they _have_ to be for the platform APIs to work right, but variables only used by my own code have been converted wherever I found them. In a few places there are int values that look very like booleans in _most_ of the places they're used, but have a rarely-used third value, or a distinction between different nonzero values that most users don't care about. In these cases, I've _removed_ uses of 'true' and 'false' for the return values, to emphasise that there's something more subtle going on than a simple boolean answer: - the 'multisel' field in dialog.h's list box structure, for which the GTK front end in particular recognises a difference between 1 and 2 but nearly everything else treats as boolean - the 'urgent' parameter to plug_receive, where 1 vs 2 tells you something about the specific location of the urgent pointer, but most clients only care about 0 vs 'something nonzero' - the return value of wc_match, where -1 indicates a syntax error in the wildcard. - the return values from SSH-1 RSA-key loading functions, which use -1 for 'wrong passphrase' and 0 for all other failures (so any caller which already knows it's not loading an _encrypted private_ key can treat them as boolean) - term->esc_query, and the 'query' parameter in toggle_mode in terminal.c, which _usually_ hold 0 for ESC[123h or 1 for ESC[?123h, but can also hold -1 for some other intervening character that we don't support. In a few places there's an integer that I haven't turned into a bool even though it really _can_ only take values 0 or 1 (and, as above, tried to make the call sites consistent in not calling those values true and false), on the grounds that I thought it would make it more confusing to imply that the 0 value was in some sense 'negative' or bad and the 1 positive or good: - the return value of plug_accepting uses the POSIXish convention of 0=success and nonzero=error; I think if I made it bool then I'd also want to reverse its sense, and that's a job for a separate piece of work. - the 'screen' parameter to lineptr() in terminal.c, where 0 and 1 represent the default and alternate screens. There's no obvious reason why one of those should be considered 'true' or 'positive' or 'success' - they're just indices - so I've left it as int. ssh_scp_recv had particularly confusing semantics for its previous int return value: its call sites used '<= 0' to check for error, but it never actually returned a negative number, just 0 or 1. Now the function and its call sites agree that it's a bool. In a couple of places I've renamed variables called 'ret', because I don't like that name any more - it's unclear whether it means the return value (in preparation) for the _containing_ function or the return value received from a subroutine call, and occasionally I've accidentally used the same variable for both and introduced a bug. So where one of those got in my way, I've renamed it to 'toret' or 'retd' (the latter short for 'returned') in line with my usual modern practice, but I haven't done a thorough job of finding all of them. Finally, one amusing side effect of doing this is that I've had to separate quite a few chained assignments. It used to be perfectly fine to write 'a = b = c = TRUE' when a,b,c were int and TRUE was just a the 'true' defined by stdbool.h, that idiom provokes a warning from gcc: 'suggest parentheses around assignment used as truth value'!
2018-11-02 22:23:19 +03:00
bool ssh2_connection_parse_global_request(
Add an actual SSH server program. This server is NOT SECURE! If anyone is reading this commit message, DO NOT DEPLOY IT IN A HOSTILE-FACING ENVIRONMENT! Its purpose is to speak the server end of everything PuTTY speaks on the client side, so that I can test that I haven't broken PuTTY when I reorganise its code, even things like RSA key exchange or chained auth methods which it's hard to find a server that speaks at all. (For this reason, it's declared with [UT] in the Recipe file, so that it falls into the same category as programs like testbn, which won't be installed by 'make install'.) Working title is 'Uppity', partly for 'Universal PuTTY Protocol Interaction Test Yoke', but mostly because it looks quite like the word 'PuTTY' with part of it reversed. (Apparently 'test yoke' is a very rarely used term meaning something not altogether unlike 'test harness', which is a bit of a stretch, but it'll do.) It doesn't actually _support_ everything I want yet. At the moment, it's a proof of concept only. But it has most of the machinery present, and the parts it's missing - such as chained auth methods - should be easy enough to add because I've built in the required flexibility, in the form of an AuthPolicy object which can request them if it wants to. However, the current AuthPolicy object is entirely trivial, and will let in any user with the password "weasel". (Another way in which this is not a production-ready server is that it also has no interaction with the OS's authentication system. In particular, it will not only let in any user with the same password, but it won't even change uid - it will open shells and forwardings under whatever user id you started it up as.) Currently, the program can only speak the SSH protocol on its standard I/O channels (using the new FdSocket facility), so if you want it to listen on a network port, you'll have to run it from some kind of separate listening program similar to inetd. For my own tests, I'm not even doing that: I'm just having PuTTY spawn it as a local proxy process, which also conveniently eliminates the risk of anyone hostile connecting to it. The bulk of the actual code reorganisation is already done by previous commits, so this change is _mostly_ just dropping in a new set of server-specific source files alongside the client-specific ones I created recently. The remaining changes in the shared SSH code are numerous, but all minor: - a few extra parameters to BPP and PPL constructors (e.g. 'are you in server mode?'), and pass both sets of SSH-1 protocol flags from the login to the connection layer - in server mode, unconditionally send our version string _before_ waiting for the remote one - a new hook in the SSH-1 BPP to handle enabling compression in server mode, where the message exchange works the other way round - new code in the SSH-2 BPP to do _deferred_ compression the other way round (the non-deferred version is still nicely symmetric) - in the SSH-2 transport layer, some adjustments to do key derivation either way round (swapping round the identifying letters in the various hash preimages, and making sure to list the KEXINITs in the right order) - also in the SSH-2 transport layer, an if statement that controls whether we send SERVICE_REQUEST and wait for SERVICE_ACCEPT, or vice versa - new ConnectionLayer methods for opening outgoing channels for X and agent forwardings - new functions in portfwd.c to establish listening sockets suitable for remote-to-local port forwarding (i.e. not under the direction of a Conf the way it's done on the client side).
2018-10-21 00:09:54 +03:00
struct ssh2_connection_state *s, ptrlen type, PktIn *pktin)
{
if (ptrlen_eq_string(type, "tcpip-forward")) {
char *host = mkstr(get_string(pktin));
unsigned port = get_uint32(pktin);
/* In SSH-2, the host/port we listen on are the same host/port
* we want reported back to us when a connection comes in,
* because that's what we tell the client */
Convert a lot of 'int' variables to 'bool'. My normal habit these days, in new code, is to treat int and bool as _almost_ completely separate types. I'm still willing to use C's implicit test for zero on an integer (e.g. 'if (!blob.len)' is fine, no need to spell it out as blob.len != 0), but generally, if a variable is going to be conceptually a boolean, I like to declare it bool and assign to it using 'true' or 'false' rather than 0 or 1. PuTTY is an exception, because it predates the C99 bool, and I've stuck to its existing coding style even when adding new code to it. But it's been annoying me more and more, so now that I've decided C99 bool is an acceptable thing to require from our toolchain in the first place, here's a quite thorough trawl through the source doing 'boolification'. Many variables and function parameters are now typed as bool rather than int; many assignments of 0 or 1 to those variables are now spelled 'true' or 'false'. I managed this thorough conversion with the help of a custom clang plugin that I wrote to trawl the AST and apply heuristics to point out where things might want changing. So I've even managed to do a decent job on parts of the code I haven't looked at in years! To make the plugin's work easier, I pushed platform front ends generally in the direction of using standard 'bool' in preference to platform-specific boolean types like Windows BOOL or GTK's gboolean; I've left the platform booleans in places they _have_ to be for the platform APIs to work right, but variables only used by my own code have been converted wherever I found them. In a few places there are int values that look very like booleans in _most_ of the places they're used, but have a rarely-used third value, or a distinction between different nonzero values that most users don't care about. In these cases, I've _removed_ uses of 'true' and 'false' for the return values, to emphasise that there's something more subtle going on than a simple boolean answer: - the 'multisel' field in dialog.h's list box structure, for which the GTK front end in particular recognises a difference between 1 and 2 but nearly everything else treats as boolean - the 'urgent' parameter to plug_receive, where 1 vs 2 tells you something about the specific location of the urgent pointer, but most clients only care about 0 vs 'something nonzero' - the return value of wc_match, where -1 indicates a syntax error in the wildcard. - the return values from SSH-1 RSA-key loading functions, which use -1 for 'wrong passphrase' and 0 for all other failures (so any caller which already knows it's not loading an _encrypted private_ key can treat them as boolean) - term->esc_query, and the 'query' parameter in toggle_mode in terminal.c, which _usually_ hold 0 for ESC[123h or 1 for ESC[?123h, but can also hold -1 for some other intervening character that we don't support. In a few places there's an integer that I haven't turned into a bool even though it really _can_ only take values 0 or 1 (and, as above, tried to make the call sites consistent in not calling those values true and false), on the grounds that I thought it would make it more confusing to imply that the 0 value was in some sense 'negative' or bad and the 1 positive or good: - the return value of plug_accepting uses the POSIXish convention of 0=success and nonzero=error; I think if I made it bool then I'd also want to reverse its sense, and that's a job for a separate piece of work. - the 'screen' parameter to lineptr() in terminal.c, where 0 and 1 represent the default and alternate screens. There's no obvious reason why one of those should be considered 'true' or 'positive' or 'success' - they're just indices - so I've left it as int. ssh_scp_recv had particularly confusing semantics for its previous int return value: its call sites used '<= 0' to check for error, but it never actually returned a negative number, just 0 or 1. Now the function and its call sites agree that it's a bool. In a couple of places I've renamed variables called 'ret', because I don't like that name any more - it's unclear whether it means the return value (in preparation) for the _containing_ function or the return value received from a subroutine call, and occasionally I've accidentally used the same variable for both and introduced a bug. So where one of those got in my way, I've renamed it to 'toret' or 'retd' (the latter short for 'returned') in line with my usual modern practice, but I haven't done a thorough job of finding all of them. Finally, one amusing side effect of doing this is that I've had to separate quite a few chained assignments. It used to be perfectly fine to write 'a = b = c = TRUE' when a,b,c were int and TRUE was just a the 'true' defined by stdbool.h, that idiom provokes a warning from gcc: 'suggest parentheses around assignment used as truth value'!
2018-11-02 22:23:19 +03:00
bool toret = portfwdmgr_listen(
Add an actual SSH server program. This server is NOT SECURE! If anyone is reading this commit message, DO NOT DEPLOY IT IN A HOSTILE-FACING ENVIRONMENT! Its purpose is to speak the server end of everything PuTTY speaks on the client side, so that I can test that I haven't broken PuTTY when I reorganise its code, even things like RSA key exchange or chained auth methods which it's hard to find a server that speaks at all. (For this reason, it's declared with [UT] in the Recipe file, so that it falls into the same category as programs like testbn, which won't be installed by 'make install'.) Working title is 'Uppity', partly for 'Universal PuTTY Protocol Interaction Test Yoke', but mostly because it looks quite like the word 'PuTTY' with part of it reversed. (Apparently 'test yoke' is a very rarely used term meaning something not altogether unlike 'test harness', which is a bit of a stretch, but it'll do.) It doesn't actually _support_ everything I want yet. At the moment, it's a proof of concept only. But it has most of the machinery present, and the parts it's missing - such as chained auth methods - should be easy enough to add because I've built in the required flexibility, in the form of an AuthPolicy object which can request them if it wants to. However, the current AuthPolicy object is entirely trivial, and will let in any user with the password "weasel". (Another way in which this is not a production-ready server is that it also has no interaction with the OS's authentication system. In particular, it will not only let in any user with the same password, but it won't even change uid - it will open shells and forwardings under whatever user id you started it up as.) Currently, the program can only speak the SSH protocol on its standard I/O channels (using the new FdSocket facility), so if you want it to listen on a network port, you'll have to run it from some kind of separate listening program similar to inetd. For my own tests, I'm not even doing that: I'm just having PuTTY spawn it as a local proxy process, which also conveniently eliminates the risk of anyone hostile connecting to it. The bulk of the actual code reorganisation is already done by previous commits, so this change is _mostly_ just dropping in a new set of server-specific source files alongside the client-specific ones I created recently. The remaining changes in the shared SSH code are numerous, but all minor: - a few extra parameters to BPP and PPL constructors (e.g. 'are you in server mode?'), and pass both sets of SSH-1 protocol flags from the login to the connection layer - in server mode, unconditionally send our version string _before_ waiting for the remote one - a new hook in the SSH-1 BPP to handle enabling compression in server mode, where the message exchange works the other way round - new code in the SSH-2 BPP to do _deferred_ compression the other way round (the non-deferred version is still nicely symmetric) - in the SSH-2 transport layer, some adjustments to do key derivation either way round (swapping round the identifying letters in the various hash preimages, and making sure to list the KEXINITs in the right order) - also in the SSH-2 transport layer, an if statement that controls whether we send SERVICE_REQUEST and wait for SERVICE_ACCEPT, or vice versa - new ConnectionLayer methods for opening outgoing channels for X and agent forwardings - new functions in portfwd.c to establish listening sockets suitable for remote-to-local port forwarding (i.e. not under the direction of a Conf the way it's done on the client side).
2018-10-21 00:09:54 +03:00
s->portfwdmgr, host, port, host, port, s->conf);
sfree(host);
return toret;
} else if (ptrlen_eq_string(type, "cancel-tcpip-forward")) {
char *host = mkstr(get_string(pktin));
unsigned port = get_uint32(pktin);
Convert a lot of 'int' variables to 'bool'. My normal habit these days, in new code, is to treat int and bool as _almost_ completely separate types. I'm still willing to use C's implicit test for zero on an integer (e.g. 'if (!blob.len)' is fine, no need to spell it out as blob.len != 0), but generally, if a variable is going to be conceptually a boolean, I like to declare it bool and assign to it using 'true' or 'false' rather than 0 or 1. PuTTY is an exception, because it predates the C99 bool, and I've stuck to its existing coding style even when adding new code to it. But it's been annoying me more and more, so now that I've decided C99 bool is an acceptable thing to require from our toolchain in the first place, here's a quite thorough trawl through the source doing 'boolification'. Many variables and function parameters are now typed as bool rather than int; many assignments of 0 or 1 to those variables are now spelled 'true' or 'false'. I managed this thorough conversion with the help of a custom clang plugin that I wrote to trawl the AST and apply heuristics to point out where things might want changing. So I've even managed to do a decent job on parts of the code I haven't looked at in years! To make the plugin's work easier, I pushed platform front ends generally in the direction of using standard 'bool' in preference to platform-specific boolean types like Windows BOOL or GTK's gboolean; I've left the platform booleans in places they _have_ to be for the platform APIs to work right, but variables only used by my own code have been converted wherever I found them. In a few places there are int values that look very like booleans in _most_ of the places they're used, but have a rarely-used third value, or a distinction between different nonzero values that most users don't care about. In these cases, I've _removed_ uses of 'true' and 'false' for the return values, to emphasise that there's something more subtle going on than a simple boolean answer: - the 'multisel' field in dialog.h's list box structure, for which the GTK front end in particular recognises a difference between 1 and 2 but nearly everything else treats as boolean - the 'urgent' parameter to plug_receive, where 1 vs 2 tells you something about the specific location of the urgent pointer, but most clients only care about 0 vs 'something nonzero' - the return value of wc_match, where -1 indicates a syntax error in the wildcard. - the return values from SSH-1 RSA-key loading functions, which use -1 for 'wrong passphrase' and 0 for all other failures (so any caller which already knows it's not loading an _encrypted private_ key can treat them as boolean) - term->esc_query, and the 'query' parameter in toggle_mode in terminal.c, which _usually_ hold 0 for ESC[123h or 1 for ESC[?123h, but can also hold -1 for some other intervening character that we don't support. In a few places there's an integer that I haven't turned into a bool even though it really _can_ only take values 0 or 1 (and, as above, tried to make the call sites consistent in not calling those values true and false), on the grounds that I thought it would make it more confusing to imply that the 0 value was in some sense 'negative' or bad and the 1 positive or good: - the return value of plug_accepting uses the POSIXish convention of 0=success and nonzero=error; I think if I made it bool then I'd also want to reverse its sense, and that's a job for a separate piece of work. - the 'screen' parameter to lineptr() in terminal.c, where 0 and 1 represent the default and alternate screens. There's no obvious reason why one of those should be considered 'true' or 'positive' or 'success' - they're just indices - so I've left it as int. ssh_scp_recv had particularly confusing semantics for its previous int return value: its call sites used '<= 0' to check for error, but it never actually returned a negative number, just 0 or 1. Now the function and its call sites agree that it's a bool. In a couple of places I've renamed variables called 'ret', because I don't like that name any more - it's unclear whether it means the return value (in preparation) for the _containing_ function or the return value received from a subroutine call, and occasionally I've accidentally used the same variable for both and introduced a bug. So where one of those got in my way, I've renamed it to 'toret' or 'retd' (the latter short for 'returned') in line with my usual modern practice, but I haven't done a thorough job of finding all of them. Finally, one amusing side effect of doing this is that I've had to separate quite a few chained assignments. It used to be perfectly fine to write 'a = b = c = TRUE' when a,b,c were int and TRUE was just a the 'true' defined by stdbool.h, that idiom provokes a warning from gcc: 'suggest parentheses around assignment used as truth value'!
2018-11-02 22:23:19 +03:00
bool toret = portfwdmgr_unlisten(s->portfwdmgr, host, port);
Add an actual SSH server program. This server is NOT SECURE! If anyone is reading this commit message, DO NOT DEPLOY IT IN A HOSTILE-FACING ENVIRONMENT! Its purpose is to speak the server end of everything PuTTY speaks on the client side, so that I can test that I haven't broken PuTTY when I reorganise its code, even things like RSA key exchange or chained auth methods which it's hard to find a server that speaks at all. (For this reason, it's declared with [UT] in the Recipe file, so that it falls into the same category as programs like testbn, which won't be installed by 'make install'.) Working title is 'Uppity', partly for 'Universal PuTTY Protocol Interaction Test Yoke', but mostly because it looks quite like the word 'PuTTY' with part of it reversed. (Apparently 'test yoke' is a very rarely used term meaning something not altogether unlike 'test harness', which is a bit of a stretch, but it'll do.) It doesn't actually _support_ everything I want yet. At the moment, it's a proof of concept only. But it has most of the machinery present, and the parts it's missing - such as chained auth methods - should be easy enough to add because I've built in the required flexibility, in the form of an AuthPolicy object which can request them if it wants to. However, the current AuthPolicy object is entirely trivial, and will let in any user with the password "weasel". (Another way in which this is not a production-ready server is that it also has no interaction with the OS's authentication system. In particular, it will not only let in any user with the same password, but it won't even change uid - it will open shells and forwardings under whatever user id you started it up as.) Currently, the program can only speak the SSH protocol on its standard I/O channels (using the new FdSocket facility), so if you want it to listen on a network port, you'll have to run it from some kind of separate listening program similar to inetd. For my own tests, I'm not even doing that: I'm just having PuTTY spawn it as a local proxy process, which also conveniently eliminates the risk of anyone hostile connecting to it. The bulk of the actual code reorganisation is already done by previous commits, so this change is _mostly_ just dropping in a new set of server-specific source files alongside the client-specific ones I created recently. The remaining changes in the shared SSH code are numerous, but all minor: - a few extra parameters to BPP and PPL constructors (e.g. 'are you in server mode?'), and pass both sets of SSH-1 protocol flags from the login to the connection layer - in server mode, unconditionally send our version string _before_ waiting for the remote one - a new hook in the SSH-1 BPP to handle enabling compression in server mode, where the message exchange works the other way round - new code in the SSH-2 BPP to do _deferred_ compression the other way round (the non-deferred version is still nicely symmetric) - in the SSH-2 transport layer, some adjustments to do key derivation either way round (swapping round the identifying letters in the various hash preimages, and making sure to list the KEXINITs in the right order) - also in the SSH-2 transport layer, an if statement that controls whether we send SERVICE_REQUEST and wait for SERVICE_ACCEPT, or vice versa - new ConnectionLayer methods for opening outgoing channels for X and agent forwardings - new functions in portfwd.c to establish listening sockets suitable for remote-to-local port forwarding (i.e. not under the direction of a Conf the way it's done on the client side).
2018-10-21 00:09:54 +03:00
sfree(host);
return toret;
} else {
/* Unrecognised request. */
Adopt C99 <stdbool.h>'s true/false. This commit includes <stdbool.h> from defs.h and deletes my traditional definitions of TRUE and FALSE, but other than that, it's a 100% mechanical search-and-replace transforming all uses of TRUE and FALSE into the C99-standardised lowercase spellings. No actual types are changed in this commit; that will come next. This is just getting the noise out of the way, so that subsequent commits can have a higher proportion of signal.
2018-10-29 22:50:29 +03:00
return false;
Add an actual SSH server program. This server is NOT SECURE! If anyone is reading this commit message, DO NOT DEPLOY IT IN A HOSTILE-FACING ENVIRONMENT! Its purpose is to speak the server end of everything PuTTY speaks on the client side, so that I can test that I haven't broken PuTTY when I reorganise its code, even things like RSA key exchange or chained auth methods which it's hard to find a server that speaks at all. (For this reason, it's declared with [UT] in the Recipe file, so that it falls into the same category as programs like testbn, which won't be installed by 'make install'.) Working title is 'Uppity', partly for 'Universal PuTTY Protocol Interaction Test Yoke', but mostly because it looks quite like the word 'PuTTY' with part of it reversed. (Apparently 'test yoke' is a very rarely used term meaning something not altogether unlike 'test harness', which is a bit of a stretch, but it'll do.) It doesn't actually _support_ everything I want yet. At the moment, it's a proof of concept only. But it has most of the machinery present, and the parts it's missing - such as chained auth methods - should be easy enough to add because I've built in the required flexibility, in the form of an AuthPolicy object which can request them if it wants to. However, the current AuthPolicy object is entirely trivial, and will let in any user with the password "weasel". (Another way in which this is not a production-ready server is that it also has no interaction with the OS's authentication system. In particular, it will not only let in any user with the same password, but it won't even change uid - it will open shells and forwardings under whatever user id you started it up as.) Currently, the program can only speak the SSH protocol on its standard I/O channels (using the new FdSocket facility), so if you want it to listen on a network port, you'll have to run it from some kind of separate listening program similar to inetd. For my own tests, I'm not even doing that: I'm just having PuTTY spawn it as a local proxy process, which also conveniently eliminates the risk of anyone hostile connecting to it. The bulk of the actual code reorganisation is already done by previous commits, so this change is _mostly_ just dropping in a new set of server-specific source files alongside the client-specific ones I created recently. The remaining changes in the shared SSH code are numerous, but all minor: - a few extra parameters to BPP and PPL constructors (e.g. 'are you in server mode?'), and pass both sets of SSH-1 protocol flags from the login to the connection layer - in server mode, unconditionally send our version string _before_ waiting for the remote one - a new hook in the SSH-1 BPP to handle enabling compression in server mode, where the message exchange works the other way round - new code in the SSH-2 BPP to do _deferred_ compression the other way round (the non-deferred version is still nicely symmetric) - in the SSH-2 transport layer, some adjustments to do key derivation either way round (swapping round the identifying letters in the various hash preimages, and making sure to list the KEXINITs in the right order) - also in the SSH-2 transport layer, an if statement that controls whether we send SERVICE_REQUEST and wait for SERVICE_ACCEPT, or vice versa - new ConnectionLayer methods for opening outgoing channels for X and agent forwardings - new functions in portfwd.c to establish listening sockets suitable for remote-to-local port forwarding (i.e. not under the direction of a Conf the way it's done on the client side).
2018-10-21 00:09:54 +03:00
}
}
PktOut *ssh2_portfwd_chanopen(
struct ssh2_connection_state *s, struct ssh2_channel *c,
const char *hostname, int port,
const char *description, const SocketPeerInfo *pi)
{
PacketProtocolLayer *ppl = &s->ppl; /* for ppl_logevent */
PktOut *pktout;
/*
* In server mode, this function is called by portfwdmgr in
* response to PortListeners that were set up by calling
* portfwdmgr_listen, which means that the hostname and port
* parameters will identify the listening socket on which a
* connection just came in.
*/
if (pi && pi->log_text)
Start using C99 variadic macros. In the past, I've had a lot of macros which you call with double parentheses, along the lines of debug(("format string", params)), so that the inner parens protect the commas and permit the macro to treat the whole printf-style argument list as one macro argument. That's all very well, but it's a bit inconvenient (it doesn't leave you any way to implement such a macro by prepending another argument to the list), and now this code base's rules allow C99isms, I can switch all those macros to using a single pair of parens, using the C99 ability to say '...' in the parameter list of the #define and get at the corresponding suffix of the arguments as __VA_ARGS__. So I'm doing it. I've made the following printf-style macros variadic: bpp_logevent, ppl_logevent, ppl_printf and debug. While I'm here, I've also fixed up a collection of conditioned-out calls to debug() in the Windows front end which were clearly expecting a macro with a different calling syntax, because they had an integer parameter first. If I ever have a need to condition those back in, they should actually work now.
2018-12-08 23:32:31 +03:00
ppl_logevent("Forwarding connection to listening port %s:%d from %s",
hostname, port, pi->log_text);
Add an actual SSH server program. This server is NOT SECURE! If anyone is reading this commit message, DO NOT DEPLOY IT IN A HOSTILE-FACING ENVIRONMENT! Its purpose is to speak the server end of everything PuTTY speaks on the client side, so that I can test that I haven't broken PuTTY when I reorganise its code, even things like RSA key exchange or chained auth methods which it's hard to find a server that speaks at all. (For this reason, it's declared with [UT] in the Recipe file, so that it falls into the same category as programs like testbn, which won't be installed by 'make install'.) Working title is 'Uppity', partly for 'Universal PuTTY Protocol Interaction Test Yoke', but mostly because it looks quite like the word 'PuTTY' with part of it reversed. (Apparently 'test yoke' is a very rarely used term meaning something not altogether unlike 'test harness', which is a bit of a stretch, but it'll do.) It doesn't actually _support_ everything I want yet. At the moment, it's a proof of concept only. But it has most of the machinery present, and the parts it's missing - such as chained auth methods - should be easy enough to add because I've built in the required flexibility, in the form of an AuthPolicy object which can request them if it wants to. However, the current AuthPolicy object is entirely trivial, and will let in any user with the password "weasel". (Another way in which this is not a production-ready server is that it also has no interaction with the OS's authentication system. In particular, it will not only let in any user with the same password, but it won't even change uid - it will open shells and forwardings under whatever user id you started it up as.) Currently, the program can only speak the SSH protocol on its standard I/O channels (using the new FdSocket facility), so if you want it to listen on a network port, you'll have to run it from some kind of separate listening program similar to inetd. For my own tests, I'm not even doing that: I'm just having PuTTY spawn it as a local proxy process, which also conveniently eliminates the risk of anyone hostile connecting to it. The bulk of the actual code reorganisation is already done by previous commits, so this change is _mostly_ just dropping in a new set of server-specific source files alongside the client-specific ones I created recently. The remaining changes in the shared SSH code are numerous, but all minor: - a few extra parameters to BPP and PPL constructors (e.g. 'are you in server mode?'), and pass both sets of SSH-1 protocol flags from the login to the connection layer - in server mode, unconditionally send our version string _before_ waiting for the remote one - a new hook in the SSH-1 BPP to handle enabling compression in server mode, where the message exchange works the other way round - new code in the SSH-2 BPP to do _deferred_ compression the other way round (the non-deferred version is still nicely symmetric) - in the SSH-2 transport layer, some adjustments to do key derivation either way round (swapping round the identifying letters in the various hash preimages, and making sure to list the KEXINITs in the right order) - also in the SSH-2 transport layer, an if statement that controls whether we send SERVICE_REQUEST and wait for SERVICE_ACCEPT, or vice versa - new ConnectionLayer methods for opening outgoing channels for X and agent forwardings - new functions in portfwd.c to establish listening sockets suitable for remote-to-local port forwarding (i.e. not under the direction of a Conf the way it's done on the client side).
2018-10-21 00:09:54 +03:00
else
Start using C99 variadic macros. In the past, I've had a lot of macros which you call with double parentheses, along the lines of debug(("format string", params)), so that the inner parens protect the commas and permit the macro to treat the whole printf-style argument list as one macro argument. That's all very well, but it's a bit inconvenient (it doesn't leave you any way to implement such a macro by prepending another argument to the list), and now this code base's rules allow C99isms, I can switch all those macros to using a single pair of parens, using the C99 ability to say '...' in the parameter list of the #define and get at the corresponding suffix of the arguments as __VA_ARGS__. So I'm doing it. I've made the following printf-style macros variadic: bpp_logevent, ppl_logevent, ppl_printf and debug. While I'm here, I've also fixed up a collection of conditioned-out calls to debug() in the Windows front end which were clearly expecting a macro with a different calling syntax, because they had an integer parameter first. If I ever have a need to condition those back in, they should actually work now.
2018-12-08 23:32:31 +03:00
ppl_logevent("Forwarding connection to listening port %s:%d",
hostname, port);
Add an actual SSH server program. This server is NOT SECURE! If anyone is reading this commit message, DO NOT DEPLOY IT IN A HOSTILE-FACING ENVIRONMENT! Its purpose is to speak the server end of everything PuTTY speaks on the client side, so that I can test that I haven't broken PuTTY when I reorganise its code, even things like RSA key exchange or chained auth methods which it's hard to find a server that speaks at all. (For this reason, it's declared with [UT] in the Recipe file, so that it falls into the same category as programs like testbn, which won't be installed by 'make install'.) Working title is 'Uppity', partly for 'Universal PuTTY Protocol Interaction Test Yoke', but mostly because it looks quite like the word 'PuTTY' with part of it reversed. (Apparently 'test yoke' is a very rarely used term meaning something not altogether unlike 'test harness', which is a bit of a stretch, but it'll do.) It doesn't actually _support_ everything I want yet. At the moment, it's a proof of concept only. But it has most of the machinery present, and the parts it's missing - such as chained auth methods - should be easy enough to add because I've built in the required flexibility, in the form of an AuthPolicy object which can request them if it wants to. However, the current AuthPolicy object is entirely trivial, and will let in any user with the password "weasel". (Another way in which this is not a production-ready server is that it also has no interaction with the OS's authentication system. In particular, it will not only let in any user with the same password, but it won't even change uid - it will open shells and forwardings under whatever user id you started it up as.) Currently, the program can only speak the SSH protocol on its standard I/O channels (using the new FdSocket facility), so if you want it to listen on a network port, you'll have to run it from some kind of separate listening program similar to inetd. For my own tests, I'm not even doing that: I'm just having PuTTY spawn it as a local proxy process, which also conveniently eliminates the risk of anyone hostile connecting to it. The bulk of the actual code reorganisation is already done by previous commits, so this change is _mostly_ just dropping in a new set of server-specific source files alongside the client-specific ones I created recently. The remaining changes in the shared SSH code are numerous, but all minor: - a few extra parameters to BPP and PPL constructors (e.g. 'are you in server mode?'), and pass both sets of SSH-1 protocol flags from the login to the connection layer - in server mode, unconditionally send our version string _before_ waiting for the remote one - a new hook in the SSH-1 BPP to handle enabling compression in server mode, where the message exchange works the other way round - new code in the SSH-2 BPP to do _deferred_ compression the other way round (the non-deferred version is still nicely symmetric) - in the SSH-2 transport layer, some adjustments to do key derivation either way round (swapping round the identifying letters in the various hash preimages, and making sure to list the KEXINITs in the right order) - also in the SSH-2 transport layer, an if statement that controls whether we send SERVICE_REQUEST and wait for SERVICE_ACCEPT, or vice versa - new ConnectionLayer methods for opening outgoing channels for X and agent forwardings - new functions in portfwd.c to establish listening sockets suitable for remote-to-local port forwarding (i.e. not under the direction of a Conf the way it's done on the client side).
2018-10-21 00:09:54 +03:00
pktout = ssh2_chanopen_init(c, "forwarded-tcpip");
put_stringz(pktout, hostname);
put_uint32(pktout, port);
put_stringz(pktout, (pi && pi->addr_text ? pi->addr_text : "0.0.0.0"));
put_uint32(pktout, (pi && pi->port >= 0 ? pi->port : 0));
return pktout;
}
struct ssh_rportfwd *ssh2_rportfwd_alloc(
ConnectionLayer *cl,
const char *shost, int sport, const char *dhost, int dport,
int addressfamily, const char *log_description, PortFwdRecord *pfr,
ssh_sharing_connstate *share_ctx)
{
Replace assert(false) with an unreachable() macro. Taking a leaf out of the LLVM code base: this macro still includes an assert(false) so that the message will show up in a typical build, but it follows it up with a call to a function explicitly marked as no- return. So this ought to do a better job of convincing compilers that once a code path hits this function it _really doesn't_ have to still faff about with making up a bogus return value or filling in a variable that 'might be used uninitialised' in the following code that won't be reached anyway. I've gone through the existing code looking for the assert(false) / assert(0) idiom and replaced all the ones I found with the new macro, which also meant I could remove a few pointless return statements and variable initialisations that I'd already had to put in to placate compiler front ends.
2019-01-03 11:12:19 +03:00
unreachable("Should never be called in the server");
Add an actual SSH server program. This server is NOT SECURE! If anyone is reading this commit message, DO NOT DEPLOY IT IN A HOSTILE-FACING ENVIRONMENT! Its purpose is to speak the server end of everything PuTTY speaks on the client side, so that I can test that I haven't broken PuTTY when I reorganise its code, even things like RSA key exchange or chained auth methods which it's hard to find a server that speaks at all. (For this reason, it's declared with [UT] in the Recipe file, so that it falls into the same category as programs like testbn, which won't be installed by 'make install'.) Working title is 'Uppity', partly for 'Universal PuTTY Protocol Interaction Test Yoke', but mostly because it looks quite like the word 'PuTTY' with part of it reversed. (Apparently 'test yoke' is a very rarely used term meaning something not altogether unlike 'test harness', which is a bit of a stretch, but it'll do.) It doesn't actually _support_ everything I want yet. At the moment, it's a proof of concept only. But it has most of the machinery present, and the parts it's missing - such as chained auth methods - should be easy enough to add because I've built in the required flexibility, in the form of an AuthPolicy object which can request them if it wants to. However, the current AuthPolicy object is entirely trivial, and will let in any user with the password "weasel". (Another way in which this is not a production-ready server is that it also has no interaction with the OS's authentication system. In particular, it will not only let in any user with the same password, but it won't even change uid - it will open shells and forwardings under whatever user id you started it up as.) Currently, the program can only speak the SSH protocol on its standard I/O channels (using the new FdSocket facility), so if you want it to listen on a network port, you'll have to run it from some kind of separate listening program similar to inetd. For my own tests, I'm not even doing that: I'm just having PuTTY spawn it as a local proxy process, which also conveniently eliminates the risk of anyone hostile connecting to it. The bulk of the actual code reorganisation is already done by previous commits, so this change is _mostly_ just dropping in a new set of server-specific source files alongside the client-specific ones I created recently. The remaining changes in the shared SSH code are numerous, but all minor: - a few extra parameters to BPP and PPL constructors (e.g. 'are you in server mode?'), and pass both sets of SSH-1 protocol flags from the login to the connection layer - in server mode, unconditionally send our version string _before_ waiting for the remote one - a new hook in the SSH-1 BPP to handle enabling compression in server mode, where the message exchange works the other way round - new code in the SSH-2 BPP to do _deferred_ compression the other way round (the non-deferred version is still nicely symmetric) - in the SSH-2 transport layer, some adjustments to do key derivation either way round (swapping round the identifying letters in the various hash preimages, and making sure to list the KEXINITs in the right order) - also in the SSH-2 transport layer, an if statement that controls whether we send SERVICE_REQUEST and wait for SERVICE_ACCEPT, or vice versa - new ConnectionLayer methods for opening outgoing channels for X and agent forwardings - new functions in portfwd.c to establish listening sockets suitable for remote-to-local port forwarding (i.e. not under the direction of a Conf the way it's done on the client side).
2018-10-21 00:09:54 +03:00
}
void ssh2_rportfwd_remove(ConnectionLayer *cl, struct ssh_rportfwd *rpf)
{
Replace assert(false) with an unreachable() macro. Taking a leaf out of the LLVM code base: this macro still includes an assert(false) so that the message will show up in a typical build, but it follows it up with a call to a function explicitly marked as no- return. So this ought to do a better job of convincing compilers that once a code path hits this function it _really doesn't_ have to still faff about with making up a bogus return value or filling in a variable that 'might be used uninitialised' in the following code that won't be reached anyway. I've gone through the existing code looking for the assert(false) / assert(0) idiom and replaced all the ones I found with the new macro, which also meant I could remove a few pointless return statements and variable initialisations that I'd already had to put in to placate compiler front ends.
2019-01-03 11:12:19 +03:00
unreachable("Should never be called in the server");
Add an actual SSH server program. This server is NOT SECURE! If anyone is reading this commit message, DO NOT DEPLOY IT IN A HOSTILE-FACING ENVIRONMENT! Its purpose is to speak the server end of everything PuTTY speaks on the client side, so that I can test that I haven't broken PuTTY when I reorganise its code, even things like RSA key exchange or chained auth methods which it's hard to find a server that speaks at all. (For this reason, it's declared with [UT] in the Recipe file, so that it falls into the same category as programs like testbn, which won't be installed by 'make install'.) Working title is 'Uppity', partly for 'Universal PuTTY Protocol Interaction Test Yoke', but mostly because it looks quite like the word 'PuTTY' with part of it reversed. (Apparently 'test yoke' is a very rarely used term meaning something not altogether unlike 'test harness', which is a bit of a stretch, but it'll do.) It doesn't actually _support_ everything I want yet. At the moment, it's a proof of concept only. But it has most of the machinery present, and the parts it's missing - such as chained auth methods - should be easy enough to add because I've built in the required flexibility, in the form of an AuthPolicy object which can request them if it wants to. However, the current AuthPolicy object is entirely trivial, and will let in any user with the password "weasel". (Another way in which this is not a production-ready server is that it also has no interaction with the OS's authentication system. In particular, it will not only let in any user with the same password, but it won't even change uid - it will open shells and forwardings under whatever user id you started it up as.) Currently, the program can only speak the SSH protocol on its standard I/O channels (using the new FdSocket facility), so if you want it to listen on a network port, you'll have to run it from some kind of separate listening program similar to inetd. For my own tests, I'm not even doing that: I'm just having PuTTY spawn it as a local proxy process, which also conveniently eliminates the risk of anyone hostile connecting to it. The bulk of the actual code reorganisation is already done by previous commits, so this change is _mostly_ just dropping in a new set of server-specific source files alongside the client-specific ones I created recently. The remaining changes in the shared SSH code are numerous, but all minor: - a few extra parameters to BPP and PPL constructors (e.g. 'are you in server mode?'), and pass both sets of SSH-1 protocol flags from the login to the connection layer - in server mode, unconditionally send our version string _before_ waiting for the remote one - a new hook in the SSH-1 BPP to handle enabling compression in server mode, where the message exchange works the other way round - new code in the SSH-2 BPP to do _deferred_ compression the other way round (the non-deferred version is still nicely symmetric) - in the SSH-2 transport layer, some adjustments to do key derivation either way round (swapping round the identifying letters in the various hash preimages, and making sure to list the KEXINITs in the right order) - also in the SSH-2 transport layer, an if statement that controls whether we send SERVICE_REQUEST and wait for SERVICE_ACCEPT, or vice versa - new ConnectionLayer methods for opening outgoing channels for X and agent forwardings - new functions in portfwd.c to establish listening sockets suitable for remote-to-local port forwarding (i.e. not under the direction of a Conf the way it's done on the client side).
2018-10-21 00:09:54 +03:00
}
SshChannel *ssh2_session_open(ConnectionLayer *cl, Channel *chan)
{
Replace assert(false) with an unreachable() macro. Taking a leaf out of the LLVM code base: this macro still includes an assert(false) so that the message will show up in a typical build, but it follows it up with a call to a function explicitly marked as no- return. So this ought to do a better job of convincing compilers that once a code path hits this function it _really doesn't_ have to still faff about with making up a bogus return value or filling in a variable that 'might be used uninitialised' in the following code that won't be reached anyway. I've gone through the existing code looking for the assert(false) / assert(0) idiom and replaced all the ones I found with the new macro, which also meant I could remove a few pointless return statements and variable initialisations that I'd already had to put in to placate compiler front ends.
2019-01-03 11:12:19 +03:00
unreachable("Should never be called in the server");
Add an actual SSH server program. This server is NOT SECURE! If anyone is reading this commit message, DO NOT DEPLOY IT IN A HOSTILE-FACING ENVIRONMENT! Its purpose is to speak the server end of everything PuTTY speaks on the client side, so that I can test that I haven't broken PuTTY when I reorganise its code, even things like RSA key exchange or chained auth methods which it's hard to find a server that speaks at all. (For this reason, it's declared with [UT] in the Recipe file, so that it falls into the same category as programs like testbn, which won't be installed by 'make install'.) Working title is 'Uppity', partly for 'Universal PuTTY Protocol Interaction Test Yoke', but mostly because it looks quite like the word 'PuTTY' with part of it reversed. (Apparently 'test yoke' is a very rarely used term meaning something not altogether unlike 'test harness', which is a bit of a stretch, but it'll do.) It doesn't actually _support_ everything I want yet. At the moment, it's a proof of concept only. But it has most of the machinery present, and the parts it's missing - such as chained auth methods - should be easy enough to add because I've built in the required flexibility, in the form of an AuthPolicy object which can request them if it wants to. However, the current AuthPolicy object is entirely trivial, and will let in any user with the password "weasel". (Another way in which this is not a production-ready server is that it also has no interaction with the OS's authentication system. In particular, it will not only let in any user with the same password, but it won't even change uid - it will open shells and forwardings under whatever user id you started it up as.) Currently, the program can only speak the SSH protocol on its standard I/O channels (using the new FdSocket facility), so if you want it to listen on a network port, you'll have to run it from some kind of separate listening program similar to inetd. For my own tests, I'm not even doing that: I'm just having PuTTY spawn it as a local proxy process, which also conveniently eliminates the risk of anyone hostile connecting to it. The bulk of the actual code reorganisation is already done by previous commits, so this change is _mostly_ just dropping in a new set of server-specific source files alongside the client-specific ones I created recently. The remaining changes in the shared SSH code are numerous, but all minor: - a few extra parameters to BPP and PPL constructors (e.g. 'are you in server mode?'), and pass both sets of SSH-1 protocol flags from the login to the connection layer - in server mode, unconditionally send our version string _before_ waiting for the remote one - a new hook in the SSH-1 BPP to handle enabling compression in server mode, where the message exchange works the other way round - new code in the SSH-2 BPP to do _deferred_ compression the other way round (the non-deferred version is still nicely symmetric) - in the SSH-2 transport layer, some adjustments to do key derivation either way round (swapping round the identifying letters in the various hash preimages, and making sure to list the KEXINITs in the right order) - also in the SSH-2 transport layer, an if statement that controls whether we send SERVICE_REQUEST and wait for SERVICE_ACCEPT, or vice versa - new ConnectionLayer methods for opening outgoing channels for X and agent forwardings - new functions in portfwd.c to establish listening sockets suitable for remote-to-local port forwarding (i.e. not under the direction of a Conf the way it's done on the client side).
2018-10-21 00:09:54 +03:00
}
SshChannel *ssh2_serverside_x11_open(
ConnectionLayer *cl, Channel *chan, const SocketPeerInfo *pi)
{
struct ssh2_connection_state *s =
container_of(cl, struct ssh2_connection_state, cl);
PacketProtocolLayer *ppl = &s->ppl; /* for ppl_logevent */
struct ssh2_channel *c = snew(struct ssh2_channel);
PktOut *pktout;
c->connlayer = s;
ssh2_channel_init(c);
Adopt C99 <stdbool.h>'s true/false. This commit includes <stdbool.h> from defs.h and deletes my traditional definitions of TRUE and FALSE, but other than that, it's a 100% mechanical search-and-replace transforming all uses of TRUE and FALSE into the C99-standardised lowercase spellings. No actual types are changed in this commit; that will come next. This is just getting the noise out of the way, so that subsequent commits can have a higher proportion of signal.
2018-10-29 22:50:29 +03:00
c->halfopen = true;
Add an actual SSH server program. This server is NOT SECURE! If anyone is reading this commit message, DO NOT DEPLOY IT IN A HOSTILE-FACING ENVIRONMENT! Its purpose is to speak the server end of everything PuTTY speaks on the client side, so that I can test that I haven't broken PuTTY when I reorganise its code, even things like RSA key exchange or chained auth methods which it's hard to find a server that speaks at all. (For this reason, it's declared with [UT] in the Recipe file, so that it falls into the same category as programs like testbn, which won't be installed by 'make install'.) Working title is 'Uppity', partly for 'Universal PuTTY Protocol Interaction Test Yoke', but mostly because it looks quite like the word 'PuTTY' with part of it reversed. (Apparently 'test yoke' is a very rarely used term meaning something not altogether unlike 'test harness', which is a bit of a stretch, but it'll do.) It doesn't actually _support_ everything I want yet. At the moment, it's a proof of concept only. But it has most of the machinery present, and the parts it's missing - such as chained auth methods - should be easy enough to add because I've built in the required flexibility, in the form of an AuthPolicy object which can request them if it wants to. However, the current AuthPolicy object is entirely trivial, and will let in any user with the password "weasel". (Another way in which this is not a production-ready server is that it also has no interaction with the OS's authentication system. In particular, it will not only let in any user with the same password, but it won't even change uid - it will open shells and forwardings under whatever user id you started it up as.) Currently, the program can only speak the SSH protocol on its standard I/O channels (using the new FdSocket facility), so if you want it to listen on a network port, you'll have to run it from some kind of separate listening program similar to inetd. For my own tests, I'm not even doing that: I'm just having PuTTY spawn it as a local proxy process, which also conveniently eliminates the risk of anyone hostile connecting to it. The bulk of the actual code reorganisation is already done by previous commits, so this change is _mostly_ just dropping in a new set of server-specific source files alongside the client-specific ones I created recently. The remaining changes in the shared SSH code are numerous, but all minor: - a few extra parameters to BPP and PPL constructors (e.g. 'are you in server mode?'), and pass both sets of SSH-1 protocol flags from the login to the connection layer - in server mode, unconditionally send our version string _before_ waiting for the remote one - a new hook in the SSH-1 BPP to handle enabling compression in server mode, where the message exchange works the other way round - new code in the SSH-2 BPP to do _deferred_ compression the other way round (the non-deferred version is still nicely symmetric) - in the SSH-2 transport layer, some adjustments to do key derivation either way round (swapping round the identifying letters in the various hash preimages, and making sure to list the KEXINITs in the right order) - also in the SSH-2 transport layer, an if statement that controls whether we send SERVICE_REQUEST and wait for SERVICE_ACCEPT, or vice versa - new ConnectionLayer methods for opening outgoing channels for X and agent forwardings - new functions in portfwd.c to establish listening sockets suitable for remote-to-local port forwarding (i.e. not under the direction of a Conf the way it's done on the client side).
2018-10-21 00:09:54 +03:00
c->chan = chan;
Start using C99 variadic macros. In the past, I've had a lot of macros which you call with double parentheses, along the lines of debug(("format string", params)), so that the inner parens protect the commas and permit the macro to treat the whole printf-style argument list as one macro argument. That's all very well, but it's a bit inconvenient (it doesn't leave you any way to implement such a macro by prepending another argument to the list), and now this code base's rules allow C99isms, I can switch all those macros to using a single pair of parens, using the C99 ability to say '...' in the parameter list of the #define and get at the corresponding suffix of the arguments as __VA_ARGS__. So I'm doing it. I've made the following printf-style macros variadic: bpp_logevent, ppl_logevent, ppl_printf and debug. While I'm here, I've also fixed up a collection of conditioned-out calls to debug() in the Windows front end which were clearly expecting a macro with a different calling syntax, because they had an integer parameter first. If I ever have a need to condition those back in, they should actually work now.
2018-12-08 23:32:31 +03:00
ppl_logevent("Forwarding X11 channel to client");
Add an actual SSH server program. This server is NOT SECURE! If anyone is reading this commit message, DO NOT DEPLOY IT IN A HOSTILE-FACING ENVIRONMENT! Its purpose is to speak the server end of everything PuTTY speaks on the client side, so that I can test that I haven't broken PuTTY when I reorganise its code, even things like RSA key exchange or chained auth methods which it's hard to find a server that speaks at all. (For this reason, it's declared with [UT] in the Recipe file, so that it falls into the same category as programs like testbn, which won't be installed by 'make install'.) Working title is 'Uppity', partly for 'Universal PuTTY Protocol Interaction Test Yoke', but mostly because it looks quite like the word 'PuTTY' with part of it reversed. (Apparently 'test yoke' is a very rarely used term meaning something not altogether unlike 'test harness', which is a bit of a stretch, but it'll do.) It doesn't actually _support_ everything I want yet. At the moment, it's a proof of concept only. But it has most of the machinery present, and the parts it's missing - such as chained auth methods - should be easy enough to add because I've built in the required flexibility, in the form of an AuthPolicy object which can request them if it wants to. However, the current AuthPolicy object is entirely trivial, and will let in any user with the password "weasel". (Another way in which this is not a production-ready server is that it also has no interaction with the OS's authentication system. In particular, it will not only let in any user with the same password, but it won't even change uid - it will open shells and forwardings under whatever user id you started it up as.) Currently, the program can only speak the SSH protocol on its standard I/O channels (using the new FdSocket facility), so if you want it to listen on a network port, you'll have to run it from some kind of separate listening program similar to inetd. For my own tests, I'm not even doing that: I'm just having PuTTY spawn it as a local proxy process, which also conveniently eliminates the risk of anyone hostile connecting to it. The bulk of the actual code reorganisation is already done by previous commits, so this change is _mostly_ just dropping in a new set of server-specific source files alongside the client-specific ones I created recently. The remaining changes in the shared SSH code are numerous, but all minor: - a few extra parameters to BPP and PPL constructors (e.g. 'are you in server mode?'), and pass both sets of SSH-1 protocol flags from the login to the connection layer - in server mode, unconditionally send our version string _before_ waiting for the remote one - a new hook in the SSH-1 BPP to handle enabling compression in server mode, where the message exchange works the other way round - new code in the SSH-2 BPP to do _deferred_ compression the other way round (the non-deferred version is still nicely symmetric) - in the SSH-2 transport layer, some adjustments to do key derivation either way round (swapping round the identifying letters in the various hash preimages, and making sure to list the KEXINITs in the right order) - also in the SSH-2 transport layer, an if statement that controls whether we send SERVICE_REQUEST and wait for SERVICE_ACCEPT, or vice versa - new ConnectionLayer methods for opening outgoing channels for X and agent forwardings - new functions in portfwd.c to establish listening sockets suitable for remote-to-local port forwarding (i.e. not under the direction of a Conf the way it's done on the client side).
2018-10-21 00:09:54 +03:00
pktout = ssh2_chanopen_init(c, "x11");
put_stringz(pktout, (pi && pi->addr_text ? pi->addr_text : "0.0.0.0"));
put_uint32(pktout, (pi && pi->port >= 0 ? pi->port : 0));
pq_push(s->ppl.out_pq, pktout);
return &c->sc;
}
SshChannel *ssh2_serverside_agent_open(ConnectionLayer *cl, Channel *chan)
{
struct ssh2_connection_state *s =
container_of(cl, struct ssh2_connection_state, cl);
PacketProtocolLayer *ppl = &s->ppl; /* for ppl_logevent */
struct ssh2_channel *c = snew(struct ssh2_channel);
PktOut *pktout;
c->connlayer = s;
ssh2_channel_init(c);
Adopt C99 <stdbool.h>'s true/false. This commit includes <stdbool.h> from defs.h and deletes my traditional definitions of TRUE and FALSE, but other than that, it's a 100% mechanical search-and-replace transforming all uses of TRUE and FALSE into the C99-standardised lowercase spellings. No actual types are changed in this commit; that will come next. This is just getting the noise out of the way, so that subsequent commits can have a higher proportion of signal.
2018-10-29 22:50:29 +03:00
c->halfopen = true;
Add an actual SSH server program. This server is NOT SECURE! If anyone is reading this commit message, DO NOT DEPLOY IT IN A HOSTILE-FACING ENVIRONMENT! Its purpose is to speak the server end of everything PuTTY speaks on the client side, so that I can test that I haven't broken PuTTY when I reorganise its code, even things like RSA key exchange or chained auth methods which it's hard to find a server that speaks at all. (For this reason, it's declared with [UT] in the Recipe file, so that it falls into the same category as programs like testbn, which won't be installed by 'make install'.) Working title is 'Uppity', partly for 'Universal PuTTY Protocol Interaction Test Yoke', but mostly because it looks quite like the word 'PuTTY' with part of it reversed. (Apparently 'test yoke' is a very rarely used term meaning something not altogether unlike 'test harness', which is a bit of a stretch, but it'll do.) It doesn't actually _support_ everything I want yet. At the moment, it's a proof of concept only. But it has most of the machinery present, and the parts it's missing - such as chained auth methods - should be easy enough to add because I've built in the required flexibility, in the form of an AuthPolicy object which can request them if it wants to. However, the current AuthPolicy object is entirely trivial, and will let in any user with the password "weasel". (Another way in which this is not a production-ready server is that it also has no interaction with the OS's authentication system. In particular, it will not only let in any user with the same password, but it won't even change uid - it will open shells and forwardings under whatever user id you started it up as.) Currently, the program can only speak the SSH protocol on its standard I/O channels (using the new FdSocket facility), so if you want it to listen on a network port, you'll have to run it from some kind of separate listening program similar to inetd. For my own tests, I'm not even doing that: I'm just having PuTTY spawn it as a local proxy process, which also conveniently eliminates the risk of anyone hostile connecting to it. The bulk of the actual code reorganisation is already done by previous commits, so this change is _mostly_ just dropping in a new set of server-specific source files alongside the client-specific ones I created recently. The remaining changes in the shared SSH code are numerous, but all minor: - a few extra parameters to BPP and PPL constructors (e.g. 'are you in server mode?'), and pass both sets of SSH-1 protocol flags from the login to the connection layer - in server mode, unconditionally send our version string _before_ waiting for the remote one - a new hook in the SSH-1 BPP to handle enabling compression in server mode, where the message exchange works the other way round - new code in the SSH-2 BPP to do _deferred_ compression the other way round (the non-deferred version is still nicely symmetric) - in the SSH-2 transport layer, some adjustments to do key derivation either way round (swapping round the identifying letters in the various hash preimages, and making sure to list the KEXINITs in the right order) - also in the SSH-2 transport layer, an if statement that controls whether we send SERVICE_REQUEST and wait for SERVICE_ACCEPT, or vice versa - new ConnectionLayer methods for opening outgoing channels for X and agent forwardings - new functions in portfwd.c to establish listening sockets suitable for remote-to-local port forwarding (i.e. not under the direction of a Conf the way it's done on the client side).
2018-10-21 00:09:54 +03:00
c->chan = chan;
Start using C99 variadic macros. In the past, I've had a lot of macros which you call with double parentheses, along the lines of debug(("format string", params)), so that the inner parens protect the commas and permit the macro to treat the whole printf-style argument list as one macro argument. That's all very well, but it's a bit inconvenient (it doesn't leave you any way to implement such a macro by prepending another argument to the list), and now this code base's rules allow C99isms, I can switch all those macros to using a single pair of parens, using the C99 ability to say '...' in the parameter list of the #define and get at the corresponding suffix of the arguments as __VA_ARGS__. So I'm doing it. I've made the following printf-style macros variadic: bpp_logevent, ppl_logevent, ppl_printf and debug. While I'm here, I've also fixed up a collection of conditioned-out calls to debug() in the Windows front end which were clearly expecting a macro with a different calling syntax, because they had an integer parameter first. If I ever have a need to condition those back in, they should actually work now.
2018-12-08 23:32:31 +03:00
ppl_logevent("Forwarding SSH agent to client");
Add an actual SSH server program. This server is NOT SECURE! If anyone is reading this commit message, DO NOT DEPLOY IT IN A HOSTILE-FACING ENVIRONMENT! Its purpose is to speak the server end of everything PuTTY speaks on the client side, so that I can test that I haven't broken PuTTY when I reorganise its code, even things like RSA key exchange or chained auth methods which it's hard to find a server that speaks at all. (For this reason, it's declared with [UT] in the Recipe file, so that it falls into the same category as programs like testbn, which won't be installed by 'make install'.) Working title is 'Uppity', partly for 'Universal PuTTY Protocol Interaction Test Yoke', but mostly because it looks quite like the word 'PuTTY' with part of it reversed. (Apparently 'test yoke' is a very rarely used term meaning something not altogether unlike 'test harness', which is a bit of a stretch, but it'll do.) It doesn't actually _support_ everything I want yet. At the moment, it's a proof of concept only. But it has most of the machinery present, and the parts it's missing - such as chained auth methods - should be easy enough to add because I've built in the required flexibility, in the form of an AuthPolicy object which can request them if it wants to. However, the current AuthPolicy object is entirely trivial, and will let in any user with the password "weasel". (Another way in which this is not a production-ready server is that it also has no interaction with the OS's authentication system. In particular, it will not only let in any user with the same password, but it won't even change uid - it will open shells and forwardings under whatever user id you started it up as.) Currently, the program can only speak the SSH protocol on its standard I/O channels (using the new FdSocket facility), so if you want it to listen on a network port, you'll have to run it from some kind of separate listening program similar to inetd. For my own tests, I'm not even doing that: I'm just having PuTTY spawn it as a local proxy process, which also conveniently eliminates the risk of anyone hostile connecting to it. The bulk of the actual code reorganisation is already done by previous commits, so this change is _mostly_ just dropping in a new set of server-specific source files alongside the client-specific ones I created recently. The remaining changes in the shared SSH code are numerous, but all minor: - a few extra parameters to BPP and PPL constructors (e.g. 'are you in server mode?'), and pass both sets of SSH-1 protocol flags from the login to the connection layer - in server mode, unconditionally send our version string _before_ waiting for the remote one - a new hook in the SSH-1 BPP to handle enabling compression in server mode, where the message exchange works the other way round - new code in the SSH-2 BPP to do _deferred_ compression the other way round (the non-deferred version is still nicely symmetric) - in the SSH-2 transport layer, some adjustments to do key derivation either way round (swapping round the identifying letters in the various hash preimages, and making sure to list the KEXINITs in the right order) - also in the SSH-2 transport layer, an if statement that controls whether we send SERVICE_REQUEST and wait for SERVICE_ACCEPT, or vice versa - new ConnectionLayer methods for opening outgoing channels for X and agent forwardings - new functions in portfwd.c to establish listening sockets suitable for remote-to-local port forwarding (i.e. not under the direction of a Conf the way it's done on the client side).
2018-10-21 00:09:54 +03:00
pktout = ssh2_chanopen_init(c, "auth-agent@openssh.com");
pq_push(s->ppl.out_pq, pktout);
return &c->sc;
}
Convert a lot of 'int' variables to 'bool'. My normal habit these days, in new code, is to treat int and bool as _almost_ completely separate types. I'm still willing to use C's implicit test for zero on an integer (e.g. 'if (!blob.len)' is fine, no need to spell it out as blob.len != 0), but generally, if a variable is going to be conceptually a boolean, I like to declare it bool and assign to it using 'true' or 'false' rather than 0 or 1. PuTTY is an exception, because it predates the C99 bool, and I've stuck to its existing coding style even when adding new code to it. But it's been annoying me more and more, so now that I've decided C99 bool is an acceptable thing to require from our toolchain in the first place, here's a quite thorough trawl through the source doing 'boolification'. Many variables and function parameters are now typed as bool rather than int; many assignments of 0 or 1 to those variables are now spelled 'true' or 'false'. I managed this thorough conversion with the help of a custom clang plugin that I wrote to trawl the AST and apply heuristics to point out where things might want changing. So I've even managed to do a decent job on parts of the code I haven't looked at in years! To make the plugin's work easier, I pushed platform front ends generally in the direction of using standard 'bool' in preference to platform-specific boolean types like Windows BOOL or GTK's gboolean; I've left the platform booleans in places they _have_ to be for the platform APIs to work right, but variables only used by my own code have been converted wherever I found them. In a few places there are int values that look very like booleans in _most_ of the places they're used, but have a rarely-used third value, or a distinction between different nonzero values that most users don't care about. In these cases, I've _removed_ uses of 'true' and 'false' for the return values, to emphasise that there's something more subtle going on than a simple boolean answer: - the 'multisel' field in dialog.h's list box structure, for which the GTK front end in particular recognises a difference between 1 and 2 but nearly everything else treats as boolean - the 'urgent' parameter to plug_receive, where 1 vs 2 tells you something about the specific location of the urgent pointer, but most clients only care about 0 vs 'something nonzero' - the return value of wc_match, where -1 indicates a syntax error in the wildcard. - the return values from SSH-1 RSA-key loading functions, which use -1 for 'wrong passphrase' and 0 for all other failures (so any caller which already knows it's not loading an _encrypted private_ key can treat them as boolean) - term->esc_query, and the 'query' parameter in toggle_mode in terminal.c, which _usually_ hold 0 for ESC[123h or 1 for ESC[?123h, but can also hold -1 for some other intervening character that we don't support. In a few places there's an integer that I haven't turned into a bool even though it really _can_ only take values 0 or 1 (and, as above, tried to make the call sites consistent in not calling those values true and false), on the grounds that I thought it would make it more confusing to imply that the 0 value was in some sense 'negative' or bad and the 1 positive or good: - the return value of plug_accepting uses the POSIXish convention of 0=success and nonzero=error; I think if I made it bool then I'd also want to reverse its sense, and that's a job for a separate piece of work. - the 'screen' parameter to lineptr() in terminal.c, where 0 and 1 represent the default and alternate screens. There's no obvious reason why one of those should be considered 'true' or 'positive' or 'success' - they're just indices - so I've left it as int. ssh_scp_recv had particularly confusing semantics for its previous int return value: its call sites used '<= 0' to check for error, but it never actually returned a negative number, just 0 or 1. Now the function and its call sites agree that it's a bool. In a couple of places I've renamed variables called 'ret', because I don't like that name any more - it's unclear whether it means the return value (in preparation) for the _containing_ function or the return value received from a subroutine call, and occasionally I've accidentally used the same variable for both and introduced a bug. So where one of those got in my way, I've renamed it to 'toret' or 'retd' (the latter short for 'returned') in line with my usual modern practice, but I haven't done a thorough job of finding all of them. Finally, one amusing side effect of doing this is that I've had to separate quite a few chained assignments. It used to be perfectly fine to write 'a = b = c = TRUE' when a,b,c were int and TRUE was just a the 'true' defined by stdbool.h, that idiom provokes a warning from gcc: 'suggest parentheses around assignment used as truth value'!
2018-11-02 22:23:19 +03:00
void ssh2channel_start_shell(SshChannel *sc, bool want_reply)
Add an actual SSH server program. This server is NOT SECURE! If anyone is reading this commit message, DO NOT DEPLOY IT IN A HOSTILE-FACING ENVIRONMENT! Its purpose is to speak the server end of everything PuTTY speaks on the client side, so that I can test that I haven't broken PuTTY when I reorganise its code, even things like RSA key exchange or chained auth methods which it's hard to find a server that speaks at all. (For this reason, it's declared with [UT] in the Recipe file, so that it falls into the same category as programs like testbn, which won't be installed by 'make install'.) Working title is 'Uppity', partly for 'Universal PuTTY Protocol Interaction Test Yoke', but mostly because it looks quite like the word 'PuTTY' with part of it reversed. (Apparently 'test yoke' is a very rarely used term meaning something not altogether unlike 'test harness', which is a bit of a stretch, but it'll do.) It doesn't actually _support_ everything I want yet. At the moment, it's a proof of concept only. But it has most of the machinery present, and the parts it's missing - such as chained auth methods - should be easy enough to add because I've built in the required flexibility, in the form of an AuthPolicy object which can request them if it wants to. However, the current AuthPolicy object is entirely trivial, and will let in any user with the password "weasel". (Another way in which this is not a production-ready server is that it also has no interaction with the OS's authentication system. In particular, it will not only let in any user with the same password, but it won't even change uid - it will open shells and forwardings under whatever user id you started it up as.) Currently, the program can only speak the SSH protocol on its standard I/O channels (using the new FdSocket facility), so if you want it to listen on a network port, you'll have to run it from some kind of separate listening program similar to inetd. For my own tests, I'm not even doing that: I'm just having PuTTY spawn it as a local proxy process, which also conveniently eliminates the risk of anyone hostile connecting to it. The bulk of the actual code reorganisation is already done by previous commits, so this change is _mostly_ just dropping in a new set of server-specific source files alongside the client-specific ones I created recently. The remaining changes in the shared SSH code are numerous, but all minor: - a few extra parameters to BPP and PPL constructors (e.g. 'are you in server mode?'), and pass both sets of SSH-1 protocol flags from the login to the connection layer - in server mode, unconditionally send our version string _before_ waiting for the remote one - a new hook in the SSH-1 BPP to handle enabling compression in server mode, where the message exchange works the other way round - new code in the SSH-2 BPP to do _deferred_ compression the other way round (the non-deferred version is still nicely symmetric) - in the SSH-2 transport layer, some adjustments to do key derivation either way round (swapping round the identifying letters in the various hash preimages, and making sure to list the KEXINITs in the right order) - also in the SSH-2 transport layer, an if statement that controls whether we send SERVICE_REQUEST and wait for SERVICE_ACCEPT, or vice versa - new ConnectionLayer methods for opening outgoing channels for X and agent forwardings - new functions in portfwd.c to establish listening sockets suitable for remote-to-local port forwarding (i.e. not under the direction of a Conf the way it's done on the client side).
2018-10-21 00:09:54 +03:00
{
Replace assert(false) with an unreachable() macro. Taking a leaf out of the LLVM code base: this macro still includes an assert(false) so that the message will show up in a typical build, but it follows it up with a call to a function explicitly marked as no- return. So this ought to do a better job of convincing compilers that once a code path hits this function it _really doesn't_ have to still faff about with making up a bogus return value or filling in a variable that 'might be used uninitialised' in the following code that won't be reached anyway. I've gone through the existing code looking for the assert(false) / assert(0) idiom and replaced all the ones I found with the new macro, which also meant I could remove a few pointless return statements and variable initialisations that I'd already had to put in to placate compiler front ends.
2019-01-03 11:12:19 +03:00
unreachable("Should never be called in the server");
Add an actual SSH server program. This server is NOT SECURE! If anyone is reading this commit message, DO NOT DEPLOY IT IN A HOSTILE-FACING ENVIRONMENT! Its purpose is to speak the server end of everything PuTTY speaks on the client side, so that I can test that I haven't broken PuTTY when I reorganise its code, even things like RSA key exchange or chained auth methods which it's hard to find a server that speaks at all. (For this reason, it's declared with [UT] in the Recipe file, so that it falls into the same category as programs like testbn, which won't be installed by 'make install'.) Working title is 'Uppity', partly for 'Universal PuTTY Protocol Interaction Test Yoke', but mostly because it looks quite like the word 'PuTTY' with part of it reversed. (Apparently 'test yoke' is a very rarely used term meaning something not altogether unlike 'test harness', which is a bit of a stretch, but it'll do.) It doesn't actually _support_ everything I want yet. At the moment, it's a proof of concept only. But it has most of the machinery present, and the parts it's missing - such as chained auth methods - should be easy enough to add because I've built in the required flexibility, in the form of an AuthPolicy object which can request them if it wants to. However, the current AuthPolicy object is entirely trivial, and will let in any user with the password "weasel". (Another way in which this is not a production-ready server is that it also has no interaction with the OS's authentication system. In particular, it will not only let in any user with the same password, but it won't even change uid - it will open shells and forwardings under whatever user id you started it up as.) Currently, the program can only speak the SSH protocol on its standard I/O channels (using the new FdSocket facility), so if you want it to listen on a network port, you'll have to run it from some kind of separate listening program similar to inetd. For my own tests, I'm not even doing that: I'm just having PuTTY spawn it as a local proxy process, which also conveniently eliminates the risk of anyone hostile connecting to it. The bulk of the actual code reorganisation is already done by previous commits, so this change is _mostly_ just dropping in a new set of server-specific source files alongside the client-specific ones I created recently. The remaining changes in the shared SSH code are numerous, but all minor: - a few extra parameters to BPP and PPL constructors (e.g. 'are you in server mode?'), and pass both sets of SSH-1 protocol flags from the login to the connection layer - in server mode, unconditionally send our version string _before_ waiting for the remote one - a new hook in the SSH-1 BPP to handle enabling compression in server mode, where the message exchange works the other way round - new code in the SSH-2 BPP to do _deferred_ compression the other way round (the non-deferred version is still nicely symmetric) - in the SSH-2 transport layer, some adjustments to do key derivation either way round (swapping round the identifying letters in the various hash preimages, and making sure to list the KEXINITs in the right order) - also in the SSH-2 transport layer, an if statement that controls whether we send SERVICE_REQUEST and wait for SERVICE_ACCEPT, or vice versa - new ConnectionLayer methods for opening outgoing channels for X and agent forwardings - new functions in portfwd.c to establish listening sockets suitable for remote-to-local port forwarding (i.e. not under the direction of a Conf the way it's done on the client side).
2018-10-21 00:09:54 +03:00
}
void ssh2channel_start_command(
Convert a lot of 'int' variables to 'bool'. My normal habit these days, in new code, is to treat int and bool as _almost_ completely separate types. I'm still willing to use C's implicit test for zero on an integer (e.g. 'if (!blob.len)' is fine, no need to spell it out as blob.len != 0), but generally, if a variable is going to be conceptually a boolean, I like to declare it bool and assign to it using 'true' or 'false' rather than 0 or 1. PuTTY is an exception, because it predates the C99 bool, and I've stuck to its existing coding style even when adding new code to it. But it's been annoying me more and more, so now that I've decided C99 bool is an acceptable thing to require from our toolchain in the first place, here's a quite thorough trawl through the source doing 'boolification'. Many variables and function parameters are now typed as bool rather than int; many assignments of 0 or 1 to those variables are now spelled 'true' or 'false'. I managed this thorough conversion with the help of a custom clang plugin that I wrote to trawl the AST and apply heuristics to point out where things might want changing. So I've even managed to do a decent job on parts of the code I haven't looked at in years! To make the plugin's work easier, I pushed platform front ends generally in the direction of using standard 'bool' in preference to platform-specific boolean types like Windows BOOL or GTK's gboolean; I've left the platform booleans in places they _have_ to be for the platform APIs to work right, but variables only used by my own code have been converted wherever I found them. In a few places there are int values that look very like booleans in _most_ of the places they're used, but have a rarely-used third value, or a distinction between different nonzero values that most users don't care about. In these cases, I've _removed_ uses of 'true' and 'false' for the return values, to emphasise that there's something more subtle going on than a simple boolean answer: - the 'multisel' field in dialog.h's list box structure, for which the GTK front end in particular recognises a difference between 1 and 2 but nearly everything else treats as boolean - the 'urgent' parameter to plug_receive, where 1 vs 2 tells you something about the specific location of the urgent pointer, but most clients only care about 0 vs 'something nonzero' - the return value of wc_match, where -1 indicates a syntax error in the wildcard. - the return values from SSH-1 RSA-key loading functions, which use -1 for 'wrong passphrase' and 0 for all other failures (so any caller which already knows it's not loading an _encrypted private_ key can treat them as boolean) - term->esc_query, and the 'query' parameter in toggle_mode in terminal.c, which _usually_ hold 0 for ESC[123h or 1 for ESC[?123h, but can also hold -1 for some other intervening character that we don't support. In a few places there's an integer that I haven't turned into a bool even though it really _can_ only take values 0 or 1 (and, as above, tried to make the call sites consistent in not calling those values true and false), on the grounds that I thought it would make it more confusing to imply that the 0 value was in some sense 'negative' or bad and the 1 positive or good: - the return value of plug_accepting uses the POSIXish convention of 0=success and nonzero=error; I think if I made it bool then I'd also want to reverse its sense, and that's a job for a separate piece of work. - the 'screen' parameter to lineptr() in terminal.c, where 0 and 1 represent the default and alternate screens. There's no obvious reason why one of those should be considered 'true' or 'positive' or 'success' - they're just indices - so I've left it as int. ssh_scp_recv had particularly confusing semantics for its previous int return value: its call sites used '<= 0' to check for error, but it never actually returned a negative number, just 0 or 1. Now the function and its call sites agree that it's a bool. In a couple of places I've renamed variables called 'ret', because I don't like that name any more - it's unclear whether it means the return value (in preparation) for the _containing_ function or the return value received from a subroutine call, and occasionally I've accidentally used the same variable for both and introduced a bug. So where one of those got in my way, I've renamed it to 'toret' or 'retd' (the latter short for 'returned') in line with my usual modern practice, but I haven't done a thorough job of finding all of them. Finally, one amusing side effect of doing this is that I've had to separate quite a few chained assignments. It used to be perfectly fine to write 'a = b = c = TRUE' when a,b,c were int and TRUE was just a the 'true' defined by stdbool.h, that idiom provokes a warning from gcc: 'suggest parentheses around assignment used as truth value'!
2018-11-02 22:23:19 +03:00
SshChannel *sc, bool want_reply, const char *command)
Add an actual SSH server program. This server is NOT SECURE! If anyone is reading this commit message, DO NOT DEPLOY IT IN A HOSTILE-FACING ENVIRONMENT! Its purpose is to speak the server end of everything PuTTY speaks on the client side, so that I can test that I haven't broken PuTTY when I reorganise its code, even things like RSA key exchange or chained auth methods which it's hard to find a server that speaks at all. (For this reason, it's declared with [UT] in the Recipe file, so that it falls into the same category as programs like testbn, which won't be installed by 'make install'.) Working title is 'Uppity', partly for 'Universal PuTTY Protocol Interaction Test Yoke', but mostly because it looks quite like the word 'PuTTY' with part of it reversed. (Apparently 'test yoke' is a very rarely used term meaning something not altogether unlike 'test harness', which is a bit of a stretch, but it'll do.) It doesn't actually _support_ everything I want yet. At the moment, it's a proof of concept only. But it has most of the machinery present, and the parts it's missing - such as chained auth methods - should be easy enough to add because I've built in the required flexibility, in the form of an AuthPolicy object which can request them if it wants to. However, the current AuthPolicy object is entirely trivial, and will let in any user with the password "weasel". (Another way in which this is not a production-ready server is that it also has no interaction with the OS's authentication system. In particular, it will not only let in any user with the same password, but it won't even change uid - it will open shells and forwardings under whatever user id you started it up as.) Currently, the program can only speak the SSH protocol on its standard I/O channels (using the new FdSocket facility), so if you want it to listen on a network port, you'll have to run it from some kind of separate listening program similar to inetd. For my own tests, I'm not even doing that: I'm just having PuTTY spawn it as a local proxy process, which also conveniently eliminates the risk of anyone hostile connecting to it. The bulk of the actual code reorganisation is already done by previous commits, so this change is _mostly_ just dropping in a new set of server-specific source files alongside the client-specific ones I created recently. The remaining changes in the shared SSH code are numerous, but all minor: - a few extra parameters to BPP and PPL constructors (e.g. 'are you in server mode?'), and pass both sets of SSH-1 protocol flags from the login to the connection layer - in server mode, unconditionally send our version string _before_ waiting for the remote one - a new hook in the SSH-1 BPP to handle enabling compression in server mode, where the message exchange works the other way round - new code in the SSH-2 BPP to do _deferred_ compression the other way round (the non-deferred version is still nicely symmetric) - in the SSH-2 transport layer, some adjustments to do key derivation either way round (swapping round the identifying letters in the various hash preimages, and making sure to list the KEXINITs in the right order) - also in the SSH-2 transport layer, an if statement that controls whether we send SERVICE_REQUEST and wait for SERVICE_ACCEPT, or vice versa - new ConnectionLayer methods for opening outgoing channels for X and agent forwardings - new functions in portfwd.c to establish listening sockets suitable for remote-to-local port forwarding (i.e. not under the direction of a Conf the way it's done on the client side).
2018-10-21 00:09:54 +03:00
{
Replace assert(false) with an unreachable() macro. Taking a leaf out of the LLVM code base: this macro still includes an assert(false) so that the message will show up in a typical build, but it follows it up with a call to a function explicitly marked as no- return. So this ought to do a better job of convincing compilers that once a code path hits this function it _really doesn't_ have to still faff about with making up a bogus return value or filling in a variable that 'might be used uninitialised' in the following code that won't be reached anyway. I've gone through the existing code looking for the assert(false) / assert(0) idiom and replaced all the ones I found with the new macro, which also meant I could remove a few pointless return statements and variable initialisations that I'd already had to put in to placate compiler front ends.
2019-01-03 11:12:19 +03:00
unreachable("Should never be called in the server");
Add an actual SSH server program. This server is NOT SECURE! If anyone is reading this commit message, DO NOT DEPLOY IT IN A HOSTILE-FACING ENVIRONMENT! Its purpose is to speak the server end of everything PuTTY speaks on the client side, so that I can test that I haven't broken PuTTY when I reorganise its code, even things like RSA key exchange or chained auth methods which it's hard to find a server that speaks at all. (For this reason, it's declared with [UT] in the Recipe file, so that it falls into the same category as programs like testbn, which won't be installed by 'make install'.) Working title is 'Uppity', partly for 'Universal PuTTY Protocol Interaction Test Yoke', but mostly because it looks quite like the word 'PuTTY' with part of it reversed. (Apparently 'test yoke' is a very rarely used term meaning something not altogether unlike 'test harness', which is a bit of a stretch, but it'll do.) It doesn't actually _support_ everything I want yet. At the moment, it's a proof of concept only. But it has most of the machinery present, and the parts it's missing - such as chained auth methods - should be easy enough to add because I've built in the required flexibility, in the form of an AuthPolicy object which can request them if it wants to. However, the current AuthPolicy object is entirely trivial, and will let in any user with the password "weasel". (Another way in which this is not a production-ready server is that it also has no interaction with the OS's authentication system. In particular, it will not only let in any user with the same password, but it won't even change uid - it will open shells and forwardings under whatever user id you started it up as.) Currently, the program can only speak the SSH protocol on its standard I/O channels (using the new FdSocket facility), so if you want it to listen on a network port, you'll have to run it from some kind of separate listening program similar to inetd. For my own tests, I'm not even doing that: I'm just having PuTTY spawn it as a local proxy process, which also conveniently eliminates the risk of anyone hostile connecting to it. The bulk of the actual code reorganisation is already done by previous commits, so this change is _mostly_ just dropping in a new set of server-specific source files alongside the client-specific ones I created recently. The remaining changes in the shared SSH code are numerous, but all minor: - a few extra parameters to BPP and PPL constructors (e.g. 'are you in server mode?'), and pass both sets of SSH-1 protocol flags from the login to the connection layer - in server mode, unconditionally send our version string _before_ waiting for the remote one - a new hook in the SSH-1 BPP to handle enabling compression in server mode, where the message exchange works the other way round - new code in the SSH-2 BPP to do _deferred_ compression the other way round (the non-deferred version is still nicely symmetric) - in the SSH-2 transport layer, some adjustments to do key derivation either way round (swapping round the identifying letters in the various hash preimages, and making sure to list the KEXINITs in the right order) - also in the SSH-2 transport layer, an if statement that controls whether we send SERVICE_REQUEST and wait for SERVICE_ACCEPT, or vice versa - new ConnectionLayer methods for opening outgoing channels for X and agent forwardings - new functions in portfwd.c to establish listening sockets suitable for remote-to-local port forwarding (i.e. not under the direction of a Conf the way it's done on the client side).
2018-10-21 00:09:54 +03:00
}
Convert a lot of 'int' variables to 'bool'. My normal habit these days, in new code, is to treat int and bool as _almost_ completely separate types. I'm still willing to use C's implicit test for zero on an integer (e.g. 'if (!blob.len)' is fine, no need to spell it out as blob.len != 0), but generally, if a variable is going to be conceptually a boolean, I like to declare it bool and assign to it using 'true' or 'false' rather than 0 or 1. PuTTY is an exception, because it predates the C99 bool, and I've stuck to its existing coding style even when adding new code to it. But it's been annoying me more and more, so now that I've decided C99 bool is an acceptable thing to require from our toolchain in the first place, here's a quite thorough trawl through the source doing 'boolification'. Many variables and function parameters are now typed as bool rather than int; many assignments of 0 or 1 to those variables are now spelled 'true' or 'false'. I managed this thorough conversion with the help of a custom clang plugin that I wrote to trawl the AST and apply heuristics to point out where things might want changing. So I've even managed to do a decent job on parts of the code I haven't looked at in years! To make the plugin's work easier, I pushed platform front ends generally in the direction of using standard 'bool' in preference to platform-specific boolean types like Windows BOOL or GTK's gboolean; I've left the platform booleans in places they _have_ to be for the platform APIs to work right, but variables only used by my own code have been converted wherever I found them. In a few places there are int values that look very like booleans in _most_ of the places they're used, but have a rarely-used third value, or a distinction between different nonzero values that most users don't care about. In these cases, I've _removed_ uses of 'true' and 'false' for the return values, to emphasise that there's something more subtle going on than a simple boolean answer: - the 'multisel' field in dialog.h's list box structure, for which the GTK front end in particular recognises a difference between 1 and 2 but nearly everything else treats as boolean - the 'urgent' parameter to plug_receive, where 1 vs 2 tells you something about the specific location of the urgent pointer, but most clients only care about 0 vs 'something nonzero' - the return value of wc_match, where -1 indicates a syntax error in the wildcard. - the return values from SSH-1 RSA-key loading functions, which use -1 for 'wrong passphrase' and 0 for all other failures (so any caller which already knows it's not loading an _encrypted private_ key can treat them as boolean) - term->esc_query, and the 'query' parameter in toggle_mode in terminal.c, which _usually_ hold 0 for ESC[123h or 1 for ESC[?123h, but can also hold -1 for some other intervening character that we don't support. In a few places there's an integer that I haven't turned into a bool even though it really _can_ only take values 0 or 1 (and, as above, tried to make the call sites consistent in not calling those values true and false), on the grounds that I thought it would make it more confusing to imply that the 0 value was in some sense 'negative' or bad and the 1 positive or good: - the return value of plug_accepting uses the POSIXish convention of 0=success and nonzero=error; I think if I made it bool then I'd also want to reverse its sense, and that's a job for a separate piece of work. - the 'screen' parameter to lineptr() in terminal.c, where 0 and 1 represent the default and alternate screens. There's no obvious reason why one of those should be considered 'true' or 'positive' or 'success' - they're just indices - so I've left it as int. ssh_scp_recv had particularly confusing semantics for its previous int return value: its call sites used '<= 0' to check for error, but it never actually returned a negative number, just 0 or 1. Now the function and its call sites agree that it's a bool. In a couple of places I've renamed variables called 'ret', because I don't like that name any more - it's unclear whether it means the return value (in preparation) for the _containing_ function or the return value received from a subroutine call, and occasionally I've accidentally used the same variable for both and introduced a bug. So where one of those got in my way, I've renamed it to 'toret' or 'retd' (the latter short for 'returned') in line with my usual modern practice, but I haven't done a thorough job of finding all of them. Finally, one amusing side effect of doing this is that I've had to separate quite a few chained assignments. It used to be perfectly fine to write 'a = b = c = TRUE' when a,b,c were int and TRUE was just a the 'true' defined by stdbool.h, that idiom provokes a warning from gcc: 'suggest parentheses around assignment used as truth value'!
2018-11-02 22:23:19 +03:00
bool ssh2channel_start_subsystem(
SshChannel *sc, bool want_reply, const char *subsystem)
Add an actual SSH server program. This server is NOT SECURE! If anyone is reading this commit message, DO NOT DEPLOY IT IN A HOSTILE-FACING ENVIRONMENT! Its purpose is to speak the server end of everything PuTTY speaks on the client side, so that I can test that I haven't broken PuTTY when I reorganise its code, even things like RSA key exchange or chained auth methods which it's hard to find a server that speaks at all. (For this reason, it's declared with [UT] in the Recipe file, so that it falls into the same category as programs like testbn, which won't be installed by 'make install'.) Working title is 'Uppity', partly for 'Universal PuTTY Protocol Interaction Test Yoke', but mostly because it looks quite like the word 'PuTTY' with part of it reversed. (Apparently 'test yoke' is a very rarely used term meaning something not altogether unlike 'test harness', which is a bit of a stretch, but it'll do.) It doesn't actually _support_ everything I want yet. At the moment, it's a proof of concept only. But it has most of the machinery present, and the parts it's missing - such as chained auth methods - should be easy enough to add because I've built in the required flexibility, in the form of an AuthPolicy object which can request them if it wants to. However, the current AuthPolicy object is entirely trivial, and will let in any user with the password "weasel". (Another way in which this is not a production-ready server is that it also has no interaction with the OS's authentication system. In particular, it will not only let in any user with the same password, but it won't even change uid - it will open shells and forwardings under whatever user id you started it up as.) Currently, the program can only speak the SSH protocol on its standard I/O channels (using the new FdSocket facility), so if you want it to listen on a network port, you'll have to run it from some kind of separate listening program similar to inetd. For my own tests, I'm not even doing that: I'm just having PuTTY spawn it as a local proxy process, which also conveniently eliminates the risk of anyone hostile connecting to it. The bulk of the actual code reorganisation is already done by previous commits, so this change is _mostly_ just dropping in a new set of server-specific source files alongside the client-specific ones I created recently. The remaining changes in the shared SSH code are numerous, but all minor: - a few extra parameters to BPP and PPL constructors (e.g. 'are you in server mode?'), and pass both sets of SSH-1 protocol flags from the login to the connection layer - in server mode, unconditionally send our version string _before_ waiting for the remote one - a new hook in the SSH-1 BPP to handle enabling compression in server mode, where the message exchange works the other way round - new code in the SSH-2 BPP to do _deferred_ compression the other way round (the non-deferred version is still nicely symmetric) - in the SSH-2 transport layer, some adjustments to do key derivation either way round (swapping round the identifying letters in the various hash preimages, and making sure to list the KEXINITs in the right order) - also in the SSH-2 transport layer, an if statement that controls whether we send SERVICE_REQUEST and wait for SERVICE_ACCEPT, or vice versa - new ConnectionLayer methods for opening outgoing channels for X and agent forwardings - new functions in portfwd.c to establish listening sockets suitable for remote-to-local port forwarding (i.e. not under the direction of a Conf the way it's done on the client side).
2018-10-21 00:09:54 +03:00
{
Replace assert(false) with an unreachable() macro. Taking a leaf out of the LLVM code base: this macro still includes an assert(false) so that the message will show up in a typical build, but it follows it up with a call to a function explicitly marked as no- return. So this ought to do a better job of convincing compilers that once a code path hits this function it _really doesn't_ have to still faff about with making up a bogus return value or filling in a variable that 'might be used uninitialised' in the following code that won't be reached anyway. I've gone through the existing code looking for the assert(false) / assert(0) idiom and replaced all the ones I found with the new macro, which also meant I could remove a few pointless return statements and variable initialisations that I'd already had to put in to placate compiler front ends.
2019-01-03 11:12:19 +03:00
unreachable("Should never be called in the server");
Add an actual SSH server program. This server is NOT SECURE! If anyone is reading this commit message, DO NOT DEPLOY IT IN A HOSTILE-FACING ENVIRONMENT! Its purpose is to speak the server end of everything PuTTY speaks on the client side, so that I can test that I haven't broken PuTTY when I reorganise its code, even things like RSA key exchange or chained auth methods which it's hard to find a server that speaks at all. (For this reason, it's declared with [UT] in the Recipe file, so that it falls into the same category as programs like testbn, which won't be installed by 'make install'.) Working title is 'Uppity', partly for 'Universal PuTTY Protocol Interaction Test Yoke', but mostly because it looks quite like the word 'PuTTY' with part of it reversed. (Apparently 'test yoke' is a very rarely used term meaning something not altogether unlike 'test harness', which is a bit of a stretch, but it'll do.) It doesn't actually _support_ everything I want yet. At the moment, it's a proof of concept only. But it has most of the machinery present, and the parts it's missing - such as chained auth methods - should be easy enough to add because I've built in the required flexibility, in the form of an AuthPolicy object which can request them if it wants to. However, the current AuthPolicy object is entirely trivial, and will let in any user with the password "weasel". (Another way in which this is not a production-ready server is that it also has no interaction with the OS's authentication system. In particular, it will not only let in any user with the same password, but it won't even change uid - it will open shells and forwardings under whatever user id you started it up as.) Currently, the program can only speak the SSH protocol on its standard I/O channels (using the new FdSocket facility), so if you want it to listen on a network port, you'll have to run it from some kind of separate listening program similar to inetd. For my own tests, I'm not even doing that: I'm just having PuTTY spawn it as a local proxy process, which also conveniently eliminates the risk of anyone hostile connecting to it. The bulk of the actual code reorganisation is already done by previous commits, so this change is _mostly_ just dropping in a new set of server-specific source files alongside the client-specific ones I created recently. The remaining changes in the shared SSH code are numerous, but all minor: - a few extra parameters to BPP and PPL constructors (e.g. 'are you in server mode?'), and pass both sets of SSH-1 protocol flags from the login to the connection layer - in server mode, unconditionally send our version string _before_ waiting for the remote one - a new hook in the SSH-1 BPP to handle enabling compression in server mode, where the message exchange works the other way round - new code in the SSH-2 BPP to do _deferred_ compression the other way round (the non-deferred version is still nicely symmetric) - in the SSH-2 transport layer, some adjustments to do key derivation either way round (swapping round the identifying letters in the various hash preimages, and making sure to list the KEXINITs in the right order) - also in the SSH-2 transport layer, an if statement that controls whether we send SERVICE_REQUEST and wait for SERVICE_ACCEPT, or vice versa - new ConnectionLayer methods for opening outgoing channels for X and agent forwardings - new functions in portfwd.c to establish listening sockets suitable for remote-to-local port forwarding (i.e. not under the direction of a Conf the way it's done on the client side).
2018-10-21 00:09:54 +03:00
}
void ssh2channel_send_exit_status(SshChannel *sc, int status)
{
struct ssh2_channel *c = container_of(sc, struct ssh2_channel, sc);
struct ssh2_connection_state *s = c->connlayer;
PktOut *pktout = ssh2_chanreq_init(c, "exit-status", NULL, NULL);
put_uint32(pktout, status);
pq_push(s->ppl.out_pq, pktout);
}
void ssh2channel_send_exit_signal(
Convert a lot of 'int' variables to 'bool'. My normal habit these days, in new code, is to treat int and bool as _almost_ completely separate types. I'm still willing to use C's implicit test for zero on an integer (e.g. 'if (!blob.len)' is fine, no need to spell it out as blob.len != 0), but generally, if a variable is going to be conceptually a boolean, I like to declare it bool and assign to it using 'true' or 'false' rather than 0 or 1. PuTTY is an exception, because it predates the C99 bool, and I've stuck to its existing coding style even when adding new code to it. But it's been annoying me more and more, so now that I've decided C99 bool is an acceptable thing to require from our toolchain in the first place, here's a quite thorough trawl through the source doing 'boolification'. Many variables and function parameters are now typed as bool rather than int; many assignments of 0 or 1 to those variables are now spelled 'true' or 'false'. I managed this thorough conversion with the help of a custom clang plugin that I wrote to trawl the AST and apply heuristics to point out where things might want changing. So I've even managed to do a decent job on parts of the code I haven't looked at in years! To make the plugin's work easier, I pushed platform front ends generally in the direction of using standard 'bool' in preference to platform-specific boolean types like Windows BOOL or GTK's gboolean; I've left the platform booleans in places they _have_ to be for the platform APIs to work right, but variables only used by my own code have been converted wherever I found them. In a few places there are int values that look very like booleans in _most_ of the places they're used, but have a rarely-used third value, or a distinction between different nonzero values that most users don't care about. In these cases, I've _removed_ uses of 'true' and 'false' for the return values, to emphasise that there's something more subtle going on than a simple boolean answer: - the 'multisel' field in dialog.h's list box structure, for which the GTK front end in particular recognises a difference between 1 and 2 but nearly everything else treats as boolean - the 'urgent' parameter to plug_receive, where 1 vs 2 tells you something about the specific location of the urgent pointer, but most clients only care about 0 vs 'something nonzero' - the return value of wc_match, where -1 indicates a syntax error in the wildcard. - the return values from SSH-1 RSA-key loading functions, which use -1 for 'wrong passphrase' and 0 for all other failures (so any caller which already knows it's not loading an _encrypted private_ key can treat them as boolean) - term->esc_query, and the 'query' parameter in toggle_mode in terminal.c, which _usually_ hold 0 for ESC[123h or 1 for ESC[?123h, but can also hold -1 for some other intervening character that we don't support. In a few places there's an integer that I haven't turned into a bool even though it really _can_ only take values 0 or 1 (and, as above, tried to make the call sites consistent in not calling those values true and false), on the grounds that I thought it would make it more confusing to imply that the 0 value was in some sense 'negative' or bad and the 1 positive or good: - the return value of plug_accepting uses the POSIXish convention of 0=success and nonzero=error; I think if I made it bool then I'd also want to reverse its sense, and that's a job for a separate piece of work. - the 'screen' parameter to lineptr() in terminal.c, where 0 and 1 represent the default and alternate screens. There's no obvious reason why one of those should be considered 'true' or 'positive' or 'success' - they're just indices - so I've left it as int. ssh_scp_recv had particularly confusing semantics for its previous int return value: its call sites used '<= 0' to check for error, but it never actually returned a negative number, just 0 or 1. Now the function and its call sites agree that it's a bool. In a couple of places I've renamed variables called 'ret', because I don't like that name any more - it's unclear whether it means the return value (in preparation) for the _containing_ function or the return value received from a subroutine call, and occasionally I've accidentally used the same variable for both and introduced a bug. So where one of those got in my way, I've renamed it to 'toret' or 'retd' (the latter short for 'returned') in line with my usual modern practice, but I haven't done a thorough job of finding all of them. Finally, one amusing side effect of doing this is that I've had to separate quite a few chained assignments. It used to be perfectly fine to write 'a = b = c = TRUE' when a,b,c were int and TRUE was just a the 'true' defined by stdbool.h, that idiom provokes a warning from gcc: 'suggest parentheses around assignment used as truth value'!
2018-11-02 22:23:19 +03:00
SshChannel *sc, ptrlen signame, bool core_dumped, ptrlen msg)
Add an actual SSH server program. This server is NOT SECURE! If anyone is reading this commit message, DO NOT DEPLOY IT IN A HOSTILE-FACING ENVIRONMENT! Its purpose is to speak the server end of everything PuTTY speaks on the client side, so that I can test that I haven't broken PuTTY when I reorganise its code, even things like RSA key exchange or chained auth methods which it's hard to find a server that speaks at all. (For this reason, it's declared with [UT] in the Recipe file, so that it falls into the same category as programs like testbn, which won't be installed by 'make install'.) Working title is 'Uppity', partly for 'Universal PuTTY Protocol Interaction Test Yoke', but mostly because it looks quite like the word 'PuTTY' with part of it reversed. (Apparently 'test yoke' is a very rarely used term meaning something not altogether unlike 'test harness', which is a bit of a stretch, but it'll do.) It doesn't actually _support_ everything I want yet. At the moment, it's a proof of concept only. But it has most of the machinery present, and the parts it's missing - such as chained auth methods - should be easy enough to add because I've built in the required flexibility, in the form of an AuthPolicy object which can request them if it wants to. However, the current AuthPolicy object is entirely trivial, and will let in any user with the password "weasel". (Another way in which this is not a production-ready server is that it also has no interaction with the OS's authentication system. In particular, it will not only let in any user with the same password, but it won't even change uid - it will open shells and forwardings under whatever user id you started it up as.) Currently, the program can only speak the SSH protocol on its standard I/O channels (using the new FdSocket facility), so if you want it to listen on a network port, you'll have to run it from some kind of separate listening program similar to inetd. For my own tests, I'm not even doing that: I'm just having PuTTY spawn it as a local proxy process, which also conveniently eliminates the risk of anyone hostile connecting to it. The bulk of the actual code reorganisation is already done by previous commits, so this change is _mostly_ just dropping in a new set of server-specific source files alongside the client-specific ones I created recently. The remaining changes in the shared SSH code are numerous, but all minor: - a few extra parameters to BPP and PPL constructors (e.g. 'are you in server mode?'), and pass both sets of SSH-1 protocol flags from the login to the connection layer - in server mode, unconditionally send our version string _before_ waiting for the remote one - a new hook in the SSH-1 BPP to handle enabling compression in server mode, where the message exchange works the other way round - new code in the SSH-2 BPP to do _deferred_ compression the other way round (the non-deferred version is still nicely symmetric) - in the SSH-2 transport layer, some adjustments to do key derivation either way round (swapping round the identifying letters in the various hash preimages, and making sure to list the KEXINITs in the right order) - also in the SSH-2 transport layer, an if statement that controls whether we send SERVICE_REQUEST and wait for SERVICE_ACCEPT, or vice versa - new ConnectionLayer methods for opening outgoing channels for X and agent forwardings - new functions in portfwd.c to establish listening sockets suitable for remote-to-local port forwarding (i.e. not under the direction of a Conf the way it's done on the client side).
2018-10-21 00:09:54 +03:00
{
struct ssh2_channel *c = container_of(sc, struct ssh2_channel, sc);
struct ssh2_connection_state *s = c->connlayer;
PktOut *pktout = ssh2_chanreq_init(c, "exit-signal", NULL, NULL);
put_stringpl(pktout, signame);
put_bool(pktout, core_dumped);
put_stringpl(pktout, msg);
put_stringz(pktout, ""); /* language tag */
pq_push(s->ppl.out_pq, pktout);
}
void ssh2channel_send_exit_signal_numeric(
Convert a lot of 'int' variables to 'bool'. My normal habit these days, in new code, is to treat int and bool as _almost_ completely separate types. I'm still willing to use C's implicit test for zero on an integer (e.g. 'if (!blob.len)' is fine, no need to spell it out as blob.len != 0), but generally, if a variable is going to be conceptually a boolean, I like to declare it bool and assign to it using 'true' or 'false' rather than 0 or 1. PuTTY is an exception, because it predates the C99 bool, and I've stuck to its existing coding style even when adding new code to it. But it's been annoying me more and more, so now that I've decided C99 bool is an acceptable thing to require from our toolchain in the first place, here's a quite thorough trawl through the source doing 'boolification'. Many variables and function parameters are now typed as bool rather than int; many assignments of 0 or 1 to those variables are now spelled 'true' or 'false'. I managed this thorough conversion with the help of a custom clang plugin that I wrote to trawl the AST and apply heuristics to point out where things might want changing. So I've even managed to do a decent job on parts of the code I haven't looked at in years! To make the plugin's work easier, I pushed platform front ends generally in the direction of using standard 'bool' in preference to platform-specific boolean types like Windows BOOL or GTK's gboolean; I've left the platform booleans in places they _have_ to be for the platform APIs to work right, but variables only used by my own code have been converted wherever I found them. In a few places there are int values that look very like booleans in _most_ of the places they're used, but have a rarely-used third value, or a distinction between different nonzero values that most users don't care about. In these cases, I've _removed_ uses of 'true' and 'false' for the return values, to emphasise that there's something more subtle going on than a simple boolean answer: - the 'multisel' field in dialog.h's list box structure, for which the GTK front end in particular recognises a difference between 1 and 2 but nearly everything else treats as boolean - the 'urgent' parameter to plug_receive, where 1 vs 2 tells you something about the specific location of the urgent pointer, but most clients only care about 0 vs 'something nonzero' - the return value of wc_match, where -1 indicates a syntax error in the wildcard. - the return values from SSH-1 RSA-key loading functions, which use -1 for 'wrong passphrase' and 0 for all other failures (so any caller which already knows it's not loading an _encrypted private_ key can treat them as boolean) - term->esc_query, and the 'query' parameter in toggle_mode in terminal.c, which _usually_ hold 0 for ESC[123h or 1 for ESC[?123h, but can also hold -1 for some other intervening character that we don't support. In a few places there's an integer that I haven't turned into a bool even though it really _can_ only take values 0 or 1 (and, as above, tried to make the call sites consistent in not calling those values true and false), on the grounds that I thought it would make it more confusing to imply that the 0 value was in some sense 'negative' or bad and the 1 positive or good: - the return value of plug_accepting uses the POSIXish convention of 0=success and nonzero=error; I think if I made it bool then I'd also want to reverse its sense, and that's a job for a separate piece of work. - the 'screen' parameter to lineptr() in terminal.c, where 0 and 1 represent the default and alternate screens. There's no obvious reason why one of those should be considered 'true' or 'positive' or 'success' - they're just indices - so I've left it as int. ssh_scp_recv had particularly confusing semantics for its previous int return value: its call sites used '<= 0' to check for error, but it never actually returned a negative number, just 0 or 1. Now the function and its call sites agree that it's a bool. In a couple of places I've renamed variables called 'ret', because I don't like that name any more - it's unclear whether it means the return value (in preparation) for the _containing_ function or the return value received from a subroutine call, and occasionally I've accidentally used the same variable for both and introduced a bug. So where one of those got in my way, I've renamed it to 'toret' or 'retd' (the latter short for 'returned') in line with my usual modern practice, but I haven't done a thorough job of finding all of them. Finally, one amusing side effect of doing this is that I've had to separate quite a few chained assignments. It used to be perfectly fine to write 'a = b = c = TRUE' when a,b,c were int and TRUE was just a the 'true' defined by stdbool.h, that idiom provokes a warning from gcc: 'suggest parentheses around assignment used as truth value'!
2018-11-02 22:23:19 +03:00
SshChannel *sc, int signum, bool core_dumped, ptrlen msg)
Add an actual SSH server program. This server is NOT SECURE! If anyone is reading this commit message, DO NOT DEPLOY IT IN A HOSTILE-FACING ENVIRONMENT! Its purpose is to speak the server end of everything PuTTY speaks on the client side, so that I can test that I haven't broken PuTTY when I reorganise its code, even things like RSA key exchange or chained auth methods which it's hard to find a server that speaks at all. (For this reason, it's declared with [UT] in the Recipe file, so that it falls into the same category as programs like testbn, which won't be installed by 'make install'.) Working title is 'Uppity', partly for 'Universal PuTTY Protocol Interaction Test Yoke', but mostly because it looks quite like the word 'PuTTY' with part of it reversed. (Apparently 'test yoke' is a very rarely used term meaning something not altogether unlike 'test harness', which is a bit of a stretch, but it'll do.) It doesn't actually _support_ everything I want yet. At the moment, it's a proof of concept only. But it has most of the machinery present, and the parts it's missing - such as chained auth methods - should be easy enough to add because I've built in the required flexibility, in the form of an AuthPolicy object which can request them if it wants to. However, the current AuthPolicy object is entirely trivial, and will let in any user with the password "weasel". (Another way in which this is not a production-ready server is that it also has no interaction with the OS's authentication system. In particular, it will not only let in any user with the same password, but it won't even change uid - it will open shells and forwardings under whatever user id you started it up as.) Currently, the program can only speak the SSH protocol on its standard I/O channels (using the new FdSocket facility), so if you want it to listen on a network port, you'll have to run it from some kind of separate listening program similar to inetd. For my own tests, I'm not even doing that: I'm just having PuTTY spawn it as a local proxy process, which also conveniently eliminates the risk of anyone hostile connecting to it. The bulk of the actual code reorganisation is already done by previous commits, so this change is _mostly_ just dropping in a new set of server-specific source files alongside the client-specific ones I created recently. The remaining changes in the shared SSH code are numerous, but all minor: - a few extra parameters to BPP and PPL constructors (e.g. 'are you in server mode?'), and pass both sets of SSH-1 protocol flags from the login to the connection layer - in server mode, unconditionally send our version string _before_ waiting for the remote one - a new hook in the SSH-1 BPP to handle enabling compression in server mode, where the message exchange works the other way round - new code in the SSH-2 BPP to do _deferred_ compression the other way round (the non-deferred version is still nicely symmetric) - in the SSH-2 transport layer, some adjustments to do key derivation either way round (swapping round the identifying letters in the various hash preimages, and making sure to list the KEXINITs in the right order) - also in the SSH-2 transport layer, an if statement that controls whether we send SERVICE_REQUEST and wait for SERVICE_ACCEPT, or vice versa - new ConnectionLayer methods for opening outgoing channels for X and agent forwardings - new functions in portfwd.c to establish listening sockets suitable for remote-to-local port forwarding (i.e. not under the direction of a Conf the way it's done on the client side).
2018-10-21 00:09:54 +03:00
{
struct ssh2_channel *c = container_of(sc, struct ssh2_channel, sc);
struct ssh2_connection_state *s = c->connlayer;
PktOut *pktout = ssh2_chanreq_init(c, "exit-signal", NULL, NULL);
put_uint32(pktout, signum);
put_bool(pktout, core_dumped);
put_stringpl(pktout, msg);
put_stringz(pktout, ""); /* language tag */
pq_push(s->ppl.out_pq, pktout);
}
void ssh2channel_request_x11_forwarding(
Convert a lot of 'int' variables to 'bool'. My normal habit these days, in new code, is to treat int and bool as _almost_ completely separate types. I'm still willing to use C's implicit test for zero on an integer (e.g. 'if (!blob.len)' is fine, no need to spell it out as blob.len != 0), but generally, if a variable is going to be conceptually a boolean, I like to declare it bool and assign to it using 'true' or 'false' rather than 0 or 1. PuTTY is an exception, because it predates the C99 bool, and I've stuck to its existing coding style even when adding new code to it. But it's been annoying me more and more, so now that I've decided C99 bool is an acceptable thing to require from our toolchain in the first place, here's a quite thorough trawl through the source doing 'boolification'. Many variables and function parameters are now typed as bool rather than int; many assignments of 0 or 1 to those variables are now spelled 'true' or 'false'. I managed this thorough conversion with the help of a custom clang plugin that I wrote to trawl the AST and apply heuristics to point out where things might want changing. So I've even managed to do a decent job on parts of the code I haven't looked at in years! To make the plugin's work easier, I pushed platform front ends generally in the direction of using standard 'bool' in preference to platform-specific boolean types like Windows BOOL or GTK's gboolean; I've left the platform booleans in places they _have_ to be for the platform APIs to work right, but variables only used by my own code have been converted wherever I found them. In a few places there are int values that look very like booleans in _most_ of the places they're used, but have a rarely-used third value, or a distinction between different nonzero values that most users don't care about. In these cases, I've _removed_ uses of 'true' and 'false' for the return values, to emphasise that there's something more subtle going on than a simple boolean answer: - the 'multisel' field in dialog.h's list box structure, for which the GTK front end in particular recognises a difference between 1 and 2 but nearly everything else treats as boolean - the 'urgent' parameter to plug_receive, where 1 vs 2 tells you something about the specific location of the urgent pointer, but most clients only care about 0 vs 'something nonzero' - the return value of wc_match, where -1 indicates a syntax error in the wildcard. - the return values from SSH-1 RSA-key loading functions, which use -1 for 'wrong passphrase' and 0 for all other failures (so any caller which already knows it's not loading an _encrypted private_ key can treat them as boolean) - term->esc_query, and the 'query' parameter in toggle_mode in terminal.c, which _usually_ hold 0 for ESC[123h or 1 for ESC[?123h, but can also hold -1 for some other intervening character that we don't support. In a few places there's an integer that I haven't turned into a bool even though it really _can_ only take values 0 or 1 (and, as above, tried to make the call sites consistent in not calling those values true and false), on the grounds that I thought it would make it more confusing to imply that the 0 value was in some sense 'negative' or bad and the 1 positive or good: - the return value of plug_accepting uses the POSIXish convention of 0=success and nonzero=error; I think if I made it bool then I'd also want to reverse its sense, and that's a job for a separate piece of work. - the 'screen' parameter to lineptr() in terminal.c, where 0 and 1 represent the default and alternate screens. There's no obvious reason why one of those should be considered 'true' or 'positive' or 'success' - they're just indices - so I've left it as int. ssh_scp_recv had particularly confusing semantics for its previous int return value: its call sites used '<= 0' to check for error, but it never actually returned a negative number, just 0 or 1. Now the function and its call sites agree that it's a bool. In a couple of places I've renamed variables called 'ret', because I don't like that name any more - it's unclear whether it means the return value (in preparation) for the _containing_ function or the return value received from a subroutine call, and occasionally I've accidentally used the same variable for both and introduced a bug. So where one of those got in my way, I've renamed it to 'toret' or 'retd' (the latter short for 'returned') in line with my usual modern practice, but I haven't done a thorough job of finding all of them. Finally, one amusing side effect of doing this is that I've had to separate quite a few chained assignments. It used to be perfectly fine to write 'a = b = c = TRUE' when a,b,c were int and TRUE was just a the 'true' defined by stdbool.h, that idiom provokes a warning from gcc: 'suggest parentheses around assignment used as truth value'!
2018-11-02 22:23:19 +03:00
SshChannel *sc, bool want_reply, const char *authproto,
const char *authdata, int screen_number, bool oneshot)
Add an actual SSH server program. This server is NOT SECURE! If anyone is reading this commit message, DO NOT DEPLOY IT IN A HOSTILE-FACING ENVIRONMENT! Its purpose is to speak the server end of everything PuTTY speaks on the client side, so that I can test that I haven't broken PuTTY when I reorganise its code, even things like RSA key exchange or chained auth methods which it's hard to find a server that speaks at all. (For this reason, it's declared with [UT] in the Recipe file, so that it falls into the same category as programs like testbn, which won't be installed by 'make install'.) Working title is 'Uppity', partly for 'Universal PuTTY Protocol Interaction Test Yoke', but mostly because it looks quite like the word 'PuTTY' with part of it reversed. (Apparently 'test yoke' is a very rarely used term meaning something not altogether unlike 'test harness', which is a bit of a stretch, but it'll do.) It doesn't actually _support_ everything I want yet. At the moment, it's a proof of concept only. But it has most of the machinery present, and the parts it's missing - such as chained auth methods - should be easy enough to add because I've built in the required flexibility, in the form of an AuthPolicy object which can request them if it wants to. However, the current AuthPolicy object is entirely trivial, and will let in any user with the password "weasel". (Another way in which this is not a production-ready server is that it also has no interaction with the OS's authentication system. In particular, it will not only let in any user with the same password, but it won't even change uid - it will open shells and forwardings under whatever user id you started it up as.) Currently, the program can only speak the SSH protocol on its standard I/O channels (using the new FdSocket facility), so if you want it to listen on a network port, you'll have to run it from some kind of separate listening program similar to inetd. For my own tests, I'm not even doing that: I'm just having PuTTY spawn it as a local proxy process, which also conveniently eliminates the risk of anyone hostile connecting to it. The bulk of the actual code reorganisation is already done by previous commits, so this change is _mostly_ just dropping in a new set of server-specific source files alongside the client-specific ones I created recently. The remaining changes in the shared SSH code are numerous, but all minor: - a few extra parameters to BPP and PPL constructors (e.g. 'are you in server mode?'), and pass both sets of SSH-1 protocol flags from the login to the connection layer - in server mode, unconditionally send our version string _before_ waiting for the remote one - a new hook in the SSH-1 BPP to handle enabling compression in server mode, where the message exchange works the other way round - new code in the SSH-2 BPP to do _deferred_ compression the other way round (the non-deferred version is still nicely symmetric) - in the SSH-2 transport layer, some adjustments to do key derivation either way round (swapping round the identifying letters in the various hash preimages, and making sure to list the KEXINITs in the right order) - also in the SSH-2 transport layer, an if statement that controls whether we send SERVICE_REQUEST and wait for SERVICE_ACCEPT, or vice versa - new ConnectionLayer methods for opening outgoing channels for X and agent forwardings - new functions in portfwd.c to establish listening sockets suitable for remote-to-local port forwarding (i.e. not under the direction of a Conf the way it's done on the client side).
2018-10-21 00:09:54 +03:00
{
Replace assert(false) with an unreachable() macro. Taking a leaf out of the LLVM code base: this macro still includes an assert(false) so that the message will show up in a typical build, but it follows it up with a call to a function explicitly marked as no- return. So this ought to do a better job of convincing compilers that once a code path hits this function it _really doesn't_ have to still faff about with making up a bogus return value or filling in a variable that 'might be used uninitialised' in the following code that won't be reached anyway. I've gone through the existing code looking for the assert(false) / assert(0) idiom and replaced all the ones I found with the new macro, which also meant I could remove a few pointless return statements and variable initialisations that I'd already had to put in to placate compiler front ends.
2019-01-03 11:12:19 +03:00
unreachable("Should never be called in the server");
Add an actual SSH server program. This server is NOT SECURE! If anyone is reading this commit message, DO NOT DEPLOY IT IN A HOSTILE-FACING ENVIRONMENT! Its purpose is to speak the server end of everything PuTTY speaks on the client side, so that I can test that I haven't broken PuTTY when I reorganise its code, even things like RSA key exchange or chained auth methods which it's hard to find a server that speaks at all. (For this reason, it's declared with [UT] in the Recipe file, so that it falls into the same category as programs like testbn, which won't be installed by 'make install'.) Working title is 'Uppity', partly for 'Universal PuTTY Protocol Interaction Test Yoke', but mostly because it looks quite like the word 'PuTTY' with part of it reversed. (Apparently 'test yoke' is a very rarely used term meaning something not altogether unlike 'test harness', which is a bit of a stretch, but it'll do.) It doesn't actually _support_ everything I want yet. At the moment, it's a proof of concept only. But it has most of the machinery present, and the parts it's missing - such as chained auth methods - should be easy enough to add because I've built in the required flexibility, in the form of an AuthPolicy object which can request them if it wants to. However, the current AuthPolicy object is entirely trivial, and will let in any user with the password "weasel". (Another way in which this is not a production-ready server is that it also has no interaction with the OS's authentication system. In particular, it will not only let in any user with the same password, but it won't even change uid - it will open shells and forwardings under whatever user id you started it up as.) Currently, the program can only speak the SSH protocol on its standard I/O channels (using the new FdSocket facility), so if you want it to listen on a network port, you'll have to run it from some kind of separate listening program similar to inetd. For my own tests, I'm not even doing that: I'm just having PuTTY spawn it as a local proxy process, which also conveniently eliminates the risk of anyone hostile connecting to it. The bulk of the actual code reorganisation is already done by previous commits, so this change is _mostly_ just dropping in a new set of server-specific source files alongside the client-specific ones I created recently. The remaining changes in the shared SSH code are numerous, but all minor: - a few extra parameters to BPP and PPL constructors (e.g. 'are you in server mode?'), and pass both sets of SSH-1 protocol flags from the login to the connection layer - in server mode, unconditionally send our version string _before_ waiting for the remote one - a new hook in the SSH-1 BPP to handle enabling compression in server mode, where the message exchange works the other way round - new code in the SSH-2 BPP to do _deferred_ compression the other way round (the non-deferred version is still nicely symmetric) - in the SSH-2 transport layer, some adjustments to do key derivation either way round (swapping round the identifying letters in the various hash preimages, and making sure to list the KEXINITs in the right order) - also in the SSH-2 transport layer, an if statement that controls whether we send SERVICE_REQUEST and wait for SERVICE_ACCEPT, or vice versa - new ConnectionLayer methods for opening outgoing channels for X and agent forwardings - new functions in portfwd.c to establish listening sockets suitable for remote-to-local port forwarding (i.e. not under the direction of a Conf the way it's done on the client side).
2018-10-21 00:09:54 +03:00
}
Convert a lot of 'int' variables to 'bool'. My normal habit these days, in new code, is to treat int and bool as _almost_ completely separate types. I'm still willing to use C's implicit test for zero on an integer (e.g. 'if (!blob.len)' is fine, no need to spell it out as blob.len != 0), but generally, if a variable is going to be conceptually a boolean, I like to declare it bool and assign to it using 'true' or 'false' rather than 0 or 1. PuTTY is an exception, because it predates the C99 bool, and I've stuck to its existing coding style even when adding new code to it. But it's been annoying me more and more, so now that I've decided C99 bool is an acceptable thing to require from our toolchain in the first place, here's a quite thorough trawl through the source doing 'boolification'. Many variables and function parameters are now typed as bool rather than int; many assignments of 0 or 1 to those variables are now spelled 'true' or 'false'. I managed this thorough conversion with the help of a custom clang plugin that I wrote to trawl the AST and apply heuristics to point out where things might want changing. So I've even managed to do a decent job on parts of the code I haven't looked at in years! To make the plugin's work easier, I pushed platform front ends generally in the direction of using standard 'bool' in preference to platform-specific boolean types like Windows BOOL or GTK's gboolean; I've left the platform booleans in places they _have_ to be for the platform APIs to work right, but variables only used by my own code have been converted wherever I found them. In a few places there are int values that look very like booleans in _most_ of the places they're used, but have a rarely-used third value, or a distinction between different nonzero values that most users don't care about. In these cases, I've _removed_ uses of 'true' and 'false' for the return values, to emphasise that there's something more subtle going on than a simple boolean answer: - the 'multisel' field in dialog.h's list box structure, for which the GTK front end in particular recognises a difference between 1 and 2 but nearly everything else treats as boolean - the 'urgent' parameter to plug_receive, where 1 vs 2 tells you something about the specific location of the urgent pointer, but most clients only care about 0 vs 'something nonzero' - the return value of wc_match, where -1 indicates a syntax error in the wildcard. - the return values from SSH-1 RSA-key loading functions, which use -1 for 'wrong passphrase' and 0 for all other failures (so any caller which already knows it's not loading an _encrypted private_ key can treat them as boolean) - term->esc_query, and the 'query' parameter in toggle_mode in terminal.c, which _usually_ hold 0 for ESC[123h or 1 for ESC[?123h, but can also hold -1 for some other intervening character that we don't support. In a few places there's an integer that I haven't turned into a bool even though it really _can_ only take values 0 or 1 (and, as above, tried to make the call sites consistent in not calling those values true and false), on the grounds that I thought it would make it more confusing to imply that the 0 value was in some sense 'negative' or bad and the 1 positive or good: - the return value of plug_accepting uses the POSIXish convention of 0=success and nonzero=error; I think if I made it bool then I'd also want to reverse its sense, and that's a job for a separate piece of work. - the 'screen' parameter to lineptr() in terminal.c, where 0 and 1 represent the default and alternate screens. There's no obvious reason why one of those should be considered 'true' or 'positive' or 'success' - they're just indices - so I've left it as int. ssh_scp_recv had particularly confusing semantics for its previous int return value: its call sites used '<= 0' to check for error, but it never actually returned a negative number, just 0 or 1. Now the function and its call sites agree that it's a bool. In a couple of places I've renamed variables called 'ret', because I don't like that name any more - it's unclear whether it means the return value (in preparation) for the _containing_ function or the return value received from a subroutine call, and occasionally I've accidentally used the same variable for both and introduced a bug. So where one of those got in my way, I've renamed it to 'toret' or 'retd' (the latter short for 'returned') in line with my usual modern practice, but I haven't done a thorough job of finding all of them. Finally, one amusing side effect of doing this is that I've had to separate quite a few chained assignments. It used to be perfectly fine to write 'a = b = c = TRUE' when a,b,c were int and TRUE was just a the 'true' defined by stdbool.h, that idiom provokes a warning from gcc: 'suggest parentheses around assignment used as truth value'!
2018-11-02 22:23:19 +03:00
void ssh2channel_request_agent_forwarding(SshChannel *sc, bool want_reply)
Add an actual SSH server program. This server is NOT SECURE! If anyone is reading this commit message, DO NOT DEPLOY IT IN A HOSTILE-FACING ENVIRONMENT! Its purpose is to speak the server end of everything PuTTY speaks on the client side, so that I can test that I haven't broken PuTTY when I reorganise its code, even things like RSA key exchange or chained auth methods which it's hard to find a server that speaks at all. (For this reason, it's declared with [UT] in the Recipe file, so that it falls into the same category as programs like testbn, which won't be installed by 'make install'.) Working title is 'Uppity', partly for 'Universal PuTTY Protocol Interaction Test Yoke', but mostly because it looks quite like the word 'PuTTY' with part of it reversed. (Apparently 'test yoke' is a very rarely used term meaning something not altogether unlike 'test harness', which is a bit of a stretch, but it'll do.) It doesn't actually _support_ everything I want yet. At the moment, it's a proof of concept only. But it has most of the machinery present, and the parts it's missing - such as chained auth methods - should be easy enough to add because I've built in the required flexibility, in the form of an AuthPolicy object which can request them if it wants to. However, the current AuthPolicy object is entirely trivial, and will let in any user with the password "weasel". (Another way in which this is not a production-ready server is that it also has no interaction with the OS's authentication system. In particular, it will not only let in any user with the same password, but it won't even change uid - it will open shells and forwardings under whatever user id you started it up as.) Currently, the program can only speak the SSH protocol on its standard I/O channels (using the new FdSocket facility), so if you want it to listen on a network port, you'll have to run it from some kind of separate listening program similar to inetd. For my own tests, I'm not even doing that: I'm just having PuTTY spawn it as a local proxy process, which also conveniently eliminates the risk of anyone hostile connecting to it. The bulk of the actual code reorganisation is already done by previous commits, so this change is _mostly_ just dropping in a new set of server-specific source files alongside the client-specific ones I created recently. The remaining changes in the shared SSH code are numerous, but all minor: - a few extra parameters to BPP and PPL constructors (e.g. 'are you in server mode?'), and pass both sets of SSH-1 protocol flags from the login to the connection layer - in server mode, unconditionally send our version string _before_ waiting for the remote one - a new hook in the SSH-1 BPP to handle enabling compression in server mode, where the message exchange works the other way round - new code in the SSH-2 BPP to do _deferred_ compression the other way round (the non-deferred version is still nicely symmetric) - in the SSH-2 transport layer, some adjustments to do key derivation either way round (swapping round the identifying letters in the various hash preimages, and making sure to list the KEXINITs in the right order) - also in the SSH-2 transport layer, an if statement that controls whether we send SERVICE_REQUEST and wait for SERVICE_ACCEPT, or vice versa - new ConnectionLayer methods for opening outgoing channels for X and agent forwardings - new functions in portfwd.c to establish listening sockets suitable for remote-to-local port forwarding (i.e. not under the direction of a Conf the way it's done on the client side).
2018-10-21 00:09:54 +03:00
{
Replace assert(false) with an unreachable() macro. Taking a leaf out of the LLVM code base: this macro still includes an assert(false) so that the message will show up in a typical build, but it follows it up with a call to a function explicitly marked as no- return. So this ought to do a better job of convincing compilers that once a code path hits this function it _really doesn't_ have to still faff about with making up a bogus return value or filling in a variable that 'might be used uninitialised' in the following code that won't be reached anyway. I've gone through the existing code looking for the assert(false) / assert(0) idiom and replaced all the ones I found with the new macro, which also meant I could remove a few pointless return statements and variable initialisations that I'd already had to put in to placate compiler front ends.
2019-01-03 11:12:19 +03:00
unreachable("Should never be called in the server");
Add an actual SSH server program. This server is NOT SECURE! If anyone is reading this commit message, DO NOT DEPLOY IT IN A HOSTILE-FACING ENVIRONMENT! Its purpose is to speak the server end of everything PuTTY speaks on the client side, so that I can test that I haven't broken PuTTY when I reorganise its code, even things like RSA key exchange or chained auth methods which it's hard to find a server that speaks at all. (For this reason, it's declared with [UT] in the Recipe file, so that it falls into the same category as programs like testbn, which won't be installed by 'make install'.) Working title is 'Uppity', partly for 'Universal PuTTY Protocol Interaction Test Yoke', but mostly because it looks quite like the word 'PuTTY' with part of it reversed. (Apparently 'test yoke' is a very rarely used term meaning something not altogether unlike 'test harness', which is a bit of a stretch, but it'll do.) It doesn't actually _support_ everything I want yet. At the moment, it's a proof of concept only. But it has most of the machinery present, and the parts it's missing - such as chained auth methods - should be easy enough to add because I've built in the required flexibility, in the form of an AuthPolicy object which can request them if it wants to. However, the current AuthPolicy object is entirely trivial, and will let in any user with the password "weasel". (Another way in which this is not a production-ready server is that it also has no interaction with the OS's authentication system. In particular, it will not only let in any user with the same password, but it won't even change uid - it will open shells and forwardings under whatever user id you started it up as.) Currently, the program can only speak the SSH protocol on its standard I/O channels (using the new FdSocket facility), so if you want it to listen on a network port, you'll have to run it from some kind of separate listening program similar to inetd. For my own tests, I'm not even doing that: I'm just having PuTTY spawn it as a local proxy process, which also conveniently eliminates the risk of anyone hostile connecting to it. The bulk of the actual code reorganisation is already done by previous commits, so this change is _mostly_ just dropping in a new set of server-specific source files alongside the client-specific ones I created recently. The remaining changes in the shared SSH code are numerous, but all minor: - a few extra parameters to BPP and PPL constructors (e.g. 'are you in server mode?'), and pass both sets of SSH-1 protocol flags from the login to the connection layer - in server mode, unconditionally send our version string _before_ waiting for the remote one - a new hook in the SSH-1 BPP to handle enabling compression in server mode, where the message exchange works the other way round - new code in the SSH-2 BPP to do _deferred_ compression the other way round (the non-deferred version is still nicely symmetric) - in the SSH-2 transport layer, some adjustments to do key derivation either way round (swapping round the identifying letters in the various hash preimages, and making sure to list the KEXINITs in the right order) - also in the SSH-2 transport layer, an if statement that controls whether we send SERVICE_REQUEST and wait for SERVICE_ACCEPT, or vice versa - new ConnectionLayer methods for opening outgoing channels for X and agent forwardings - new functions in portfwd.c to establish listening sockets suitable for remote-to-local port forwarding (i.e. not under the direction of a Conf the way it's done on the client side).
2018-10-21 00:09:54 +03:00
}
void ssh2channel_request_pty(
Convert a lot of 'int' variables to 'bool'. My normal habit these days, in new code, is to treat int and bool as _almost_ completely separate types. I'm still willing to use C's implicit test for zero on an integer (e.g. 'if (!blob.len)' is fine, no need to spell it out as blob.len != 0), but generally, if a variable is going to be conceptually a boolean, I like to declare it bool and assign to it using 'true' or 'false' rather than 0 or 1. PuTTY is an exception, because it predates the C99 bool, and I've stuck to its existing coding style even when adding new code to it. But it's been annoying me more and more, so now that I've decided C99 bool is an acceptable thing to require from our toolchain in the first place, here's a quite thorough trawl through the source doing 'boolification'. Many variables and function parameters are now typed as bool rather than int; many assignments of 0 or 1 to those variables are now spelled 'true' or 'false'. I managed this thorough conversion with the help of a custom clang plugin that I wrote to trawl the AST and apply heuristics to point out where things might want changing. So I've even managed to do a decent job on parts of the code I haven't looked at in years! To make the plugin's work easier, I pushed platform front ends generally in the direction of using standard 'bool' in preference to platform-specific boolean types like Windows BOOL or GTK's gboolean; I've left the platform booleans in places they _have_ to be for the platform APIs to work right, but variables only used by my own code have been converted wherever I found them. In a few places there are int values that look very like booleans in _most_ of the places they're used, but have a rarely-used third value, or a distinction between different nonzero values that most users don't care about. In these cases, I've _removed_ uses of 'true' and 'false' for the return values, to emphasise that there's something more subtle going on than a simple boolean answer: - the 'multisel' field in dialog.h's list box structure, for which the GTK front end in particular recognises a difference between 1 and 2 but nearly everything else treats as boolean - the 'urgent' parameter to plug_receive, where 1 vs 2 tells you something about the specific location of the urgent pointer, but most clients only care about 0 vs 'something nonzero' - the return value of wc_match, where -1 indicates a syntax error in the wildcard. - the return values from SSH-1 RSA-key loading functions, which use -1 for 'wrong passphrase' and 0 for all other failures (so any caller which already knows it's not loading an _encrypted private_ key can treat them as boolean) - term->esc_query, and the 'query' parameter in toggle_mode in terminal.c, which _usually_ hold 0 for ESC[123h or 1 for ESC[?123h, but can also hold -1 for some other intervening character that we don't support. In a few places there's an integer that I haven't turned into a bool even though it really _can_ only take values 0 or 1 (and, as above, tried to make the call sites consistent in not calling those values true and false), on the grounds that I thought it would make it more confusing to imply that the 0 value was in some sense 'negative' or bad and the 1 positive or good: - the return value of plug_accepting uses the POSIXish convention of 0=success and nonzero=error; I think if I made it bool then I'd also want to reverse its sense, and that's a job for a separate piece of work. - the 'screen' parameter to lineptr() in terminal.c, where 0 and 1 represent the default and alternate screens. There's no obvious reason why one of those should be considered 'true' or 'positive' or 'success' - they're just indices - so I've left it as int. ssh_scp_recv had particularly confusing semantics for its previous int return value: its call sites used '<= 0' to check for error, but it never actually returned a negative number, just 0 or 1. Now the function and its call sites agree that it's a bool. In a couple of places I've renamed variables called 'ret', because I don't like that name any more - it's unclear whether it means the return value (in preparation) for the _containing_ function or the return value received from a subroutine call, and occasionally I've accidentally used the same variable for both and introduced a bug. So where one of those got in my way, I've renamed it to 'toret' or 'retd' (the latter short for 'returned') in line with my usual modern practice, but I haven't done a thorough job of finding all of them. Finally, one amusing side effect of doing this is that I've had to separate quite a few chained assignments. It used to be perfectly fine to write 'a = b = c = TRUE' when a,b,c were int and TRUE was just a the 'true' defined by stdbool.h, that idiom provokes a warning from gcc: 'suggest parentheses around assignment used as truth value'!
2018-11-02 22:23:19 +03:00
SshChannel *sc, bool want_reply, Conf *conf, int w, int h)
Add an actual SSH server program. This server is NOT SECURE! If anyone is reading this commit message, DO NOT DEPLOY IT IN A HOSTILE-FACING ENVIRONMENT! Its purpose is to speak the server end of everything PuTTY speaks on the client side, so that I can test that I haven't broken PuTTY when I reorganise its code, even things like RSA key exchange or chained auth methods which it's hard to find a server that speaks at all. (For this reason, it's declared with [UT] in the Recipe file, so that it falls into the same category as programs like testbn, which won't be installed by 'make install'.) Working title is 'Uppity', partly for 'Universal PuTTY Protocol Interaction Test Yoke', but mostly because it looks quite like the word 'PuTTY' with part of it reversed. (Apparently 'test yoke' is a very rarely used term meaning something not altogether unlike 'test harness', which is a bit of a stretch, but it'll do.) It doesn't actually _support_ everything I want yet. At the moment, it's a proof of concept only. But it has most of the machinery present, and the parts it's missing - such as chained auth methods - should be easy enough to add because I've built in the required flexibility, in the form of an AuthPolicy object which can request them if it wants to. However, the current AuthPolicy object is entirely trivial, and will let in any user with the password "weasel". (Another way in which this is not a production-ready server is that it also has no interaction with the OS's authentication system. In particular, it will not only let in any user with the same password, but it won't even change uid - it will open shells and forwardings under whatever user id you started it up as.) Currently, the program can only speak the SSH protocol on its standard I/O channels (using the new FdSocket facility), so if you want it to listen on a network port, you'll have to run it from some kind of separate listening program similar to inetd. For my own tests, I'm not even doing that: I'm just having PuTTY spawn it as a local proxy process, which also conveniently eliminates the risk of anyone hostile connecting to it. The bulk of the actual code reorganisation is already done by previous commits, so this change is _mostly_ just dropping in a new set of server-specific source files alongside the client-specific ones I created recently. The remaining changes in the shared SSH code are numerous, but all minor: - a few extra parameters to BPP and PPL constructors (e.g. 'are you in server mode?'), and pass both sets of SSH-1 protocol flags from the login to the connection layer - in server mode, unconditionally send our version string _before_ waiting for the remote one - a new hook in the SSH-1 BPP to handle enabling compression in server mode, where the message exchange works the other way round - new code in the SSH-2 BPP to do _deferred_ compression the other way round (the non-deferred version is still nicely symmetric) - in the SSH-2 transport layer, some adjustments to do key derivation either way round (swapping round the identifying letters in the various hash preimages, and making sure to list the KEXINITs in the right order) - also in the SSH-2 transport layer, an if statement that controls whether we send SERVICE_REQUEST and wait for SERVICE_ACCEPT, or vice versa - new ConnectionLayer methods for opening outgoing channels for X and agent forwardings - new functions in portfwd.c to establish listening sockets suitable for remote-to-local port forwarding (i.e. not under the direction of a Conf the way it's done on the client side).
2018-10-21 00:09:54 +03:00
{
Replace assert(false) with an unreachable() macro. Taking a leaf out of the LLVM code base: this macro still includes an assert(false) so that the message will show up in a typical build, but it follows it up with a call to a function explicitly marked as no- return. So this ought to do a better job of convincing compilers that once a code path hits this function it _really doesn't_ have to still faff about with making up a bogus return value or filling in a variable that 'might be used uninitialised' in the following code that won't be reached anyway. I've gone through the existing code looking for the assert(false) / assert(0) idiom and replaced all the ones I found with the new macro, which also meant I could remove a few pointless return statements and variable initialisations that I'd already had to put in to placate compiler front ends.
2019-01-03 11:12:19 +03:00
unreachable("Should never be called in the server");
Add an actual SSH server program. This server is NOT SECURE! If anyone is reading this commit message, DO NOT DEPLOY IT IN A HOSTILE-FACING ENVIRONMENT! Its purpose is to speak the server end of everything PuTTY speaks on the client side, so that I can test that I haven't broken PuTTY when I reorganise its code, even things like RSA key exchange or chained auth methods which it's hard to find a server that speaks at all. (For this reason, it's declared with [UT] in the Recipe file, so that it falls into the same category as programs like testbn, which won't be installed by 'make install'.) Working title is 'Uppity', partly for 'Universal PuTTY Protocol Interaction Test Yoke', but mostly because it looks quite like the word 'PuTTY' with part of it reversed. (Apparently 'test yoke' is a very rarely used term meaning something not altogether unlike 'test harness', which is a bit of a stretch, but it'll do.) It doesn't actually _support_ everything I want yet. At the moment, it's a proof of concept only. But it has most of the machinery present, and the parts it's missing - such as chained auth methods - should be easy enough to add because I've built in the required flexibility, in the form of an AuthPolicy object which can request them if it wants to. However, the current AuthPolicy object is entirely trivial, and will let in any user with the password "weasel". (Another way in which this is not a production-ready server is that it also has no interaction with the OS's authentication system. In particular, it will not only let in any user with the same password, but it won't even change uid - it will open shells and forwardings under whatever user id you started it up as.) Currently, the program can only speak the SSH protocol on its standard I/O channels (using the new FdSocket facility), so if you want it to listen on a network port, you'll have to run it from some kind of separate listening program similar to inetd. For my own tests, I'm not even doing that: I'm just having PuTTY spawn it as a local proxy process, which also conveniently eliminates the risk of anyone hostile connecting to it. The bulk of the actual code reorganisation is already done by previous commits, so this change is _mostly_ just dropping in a new set of server-specific source files alongside the client-specific ones I created recently. The remaining changes in the shared SSH code are numerous, but all minor: - a few extra parameters to BPP and PPL constructors (e.g. 'are you in server mode?'), and pass both sets of SSH-1 protocol flags from the login to the connection layer - in server mode, unconditionally send our version string _before_ waiting for the remote one - a new hook in the SSH-1 BPP to handle enabling compression in server mode, where the message exchange works the other way round - new code in the SSH-2 BPP to do _deferred_ compression the other way round (the non-deferred version is still nicely symmetric) - in the SSH-2 transport layer, some adjustments to do key derivation either way round (swapping round the identifying letters in the various hash preimages, and making sure to list the KEXINITs in the right order) - also in the SSH-2 transport layer, an if statement that controls whether we send SERVICE_REQUEST and wait for SERVICE_ACCEPT, or vice versa - new ConnectionLayer methods for opening outgoing channels for X and agent forwardings - new functions in portfwd.c to establish listening sockets suitable for remote-to-local port forwarding (i.e. not under the direction of a Conf the way it's done on the client side).
2018-10-21 00:09:54 +03:00
}
Convert a lot of 'int' variables to 'bool'. My normal habit these days, in new code, is to treat int and bool as _almost_ completely separate types. I'm still willing to use C's implicit test for zero on an integer (e.g. 'if (!blob.len)' is fine, no need to spell it out as blob.len != 0), but generally, if a variable is going to be conceptually a boolean, I like to declare it bool and assign to it using 'true' or 'false' rather than 0 or 1. PuTTY is an exception, because it predates the C99 bool, and I've stuck to its existing coding style even when adding new code to it. But it's been annoying me more and more, so now that I've decided C99 bool is an acceptable thing to require from our toolchain in the first place, here's a quite thorough trawl through the source doing 'boolification'. Many variables and function parameters are now typed as bool rather than int; many assignments of 0 or 1 to those variables are now spelled 'true' or 'false'. I managed this thorough conversion with the help of a custom clang plugin that I wrote to trawl the AST and apply heuristics to point out where things might want changing. So I've even managed to do a decent job on parts of the code I haven't looked at in years! To make the plugin's work easier, I pushed platform front ends generally in the direction of using standard 'bool' in preference to platform-specific boolean types like Windows BOOL or GTK's gboolean; I've left the platform booleans in places they _have_ to be for the platform APIs to work right, but variables only used by my own code have been converted wherever I found them. In a few places there are int values that look very like booleans in _most_ of the places they're used, but have a rarely-used third value, or a distinction between different nonzero values that most users don't care about. In these cases, I've _removed_ uses of 'true' and 'false' for the return values, to emphasise that there's something more subtle going on than a simple boolean answer: - the 'multisel' field in dialog.h's list box structure, for which the GTK front end in particular recognises a difference between 1 and 2 but nearly everything else treats as boolean - the 'urgent' parameter to plug_receive, where 1 vs 2 tells you something about the specific location of the urgent pointer, but most clients only care about 0 vs 'something nonzero' - the return value of wc_match, where -1 indicates a syntax error in the wildcard. - the return values from SSH-1 RSA-key loading functions, which use -1 for 'wrong passphrase' and 0 for all other failures (so any caller which already knows it's not loading an _encrypted private_ key can treat them as boolean) - term->esc_query, and the 'query' parameter in toggle_mode in terminal.c, which _usually_ hold 0 for ESC[123h or 1 for ESC[?123h, but can also hold -1 for some other intervening character that we don't support. In a few places there's an integer that I haven't turned into a bool even though it really _can_ only take values 0 or 1 (and, as above, tried to make the call sites consistent in not calling those values true and false), on the grounds that I thought it would make it more confusing to imply that the 0 value was in some sense 'negative' or bad and the 1 positive or good: - the return value of plug_accepting uses the POSIXish convention of 0=success and nonzero=error; I think if I made it bool then I'd also want to reverse its sense, and that's a job for a separate piece of work. - the 'screen' parameter to lineptr() in terminal.c, where 0 and 1 represent the default and alternate screens. There's no obvious reason why one of those should be considered 'true' or 'positive' or 'success' - they're just indices - so I've left it as int. ssh_scp_recv had particularly confusing semantics for its previous int return value: its call sites used '<= 0' to check for error, but it never actually returned a negative number, just 0 or 1. Now the function and its call sites agree that it's a bool. In a couple of places I've renamed variables called 'ret', because I don't like that name any more - it's unclear whether it means the return value (in preparation) for the _containing_ function or the return value received from a subroutine call, and occasionally I've accidentally used the same variable for both and introduced a bug. So where one of those got in my way, I've renamed it to 'toret' or 'retd' (the latter short for 'returned') in line with my usual modern practice, but I haven't done a thorough job of finding all of them. Finally, one amusing side effect of doing this is that I've had to separate quite a few chained assignments. It used to be perfectly fine to write 'a = b = c = TRUE' when a,b,c were int and TRUE was just a the 'true' defined by stdbool.h, that idiom provokes a warning from gcc: 'suggest parentheses around assignment used as truth value'!
2018-11-02 22:23:19 +03:00
bool ssh2channel_send_env_var(
SshChannel *sc, bool want_reply, const char *var, const char *value)
Add an actual SSH server program. This server is NOT SECURE! If anyone is reading this commit message, DO NOT DEPLOY IT IN A HOSTILE-FACING ENVIRONMENT! Its purpose is to speak the server end of everything PuTTY speaks on the client side, so that I can test that I haven't broken PuTTY when I reorganise its code, even things like RSA key exchange or chained auth methods which it's hard to find a server that speaks at all. (For this reason, it's declared with [UT] in the Recipe file, so that it falls into the same category as programs like testbn, which won't be installed by 'make install'.) Working title is 'Uppity', partly for 'Universal PuTTY Protocol Interaction Test Yoke', but mostly because it looks quite like the word 'PuTTY' with part of it reversed. (Apparently 'test yoke' is a very rarely used term meaning something not altogether unlike 'test harness', which is a bit of a stretch, but it'll do.) It doesn't actually _support_ everything I want yet. At the moment, it's a proof of concept only. But it has most of the machinery present, and the parts it's missing - such as chained auth methods - should be easy enough to add because I've built in the required flexibility, in the form of an AuthPolicy object which can request them if it wants to. However, the current AuthPolicy object is entirely trivial, and will let in any user with the password "weasel". (Another way in which this is not a production-ready server is that it also has no interaction with the OS's authentication system. In particular, it will not only let in any user with the same password, but it won't even change uid - it will open shells and forwardings under whatever user id you started it up as.) Currently, the program can only speak the SSH protocol on its standard I/O channels (using the new FdSocket facility), so if you want it to listen on a network port, you'll have to run it from some kind of separate listening program similar to inetd. For my own tests, I'm not even doing that: I'm just having PuTTY spawn it as a local proxy process, which also conveniently eliminates the risk of anyone hostile connecting to it. The bulk of the actual code reorganisation is already done by previous commits, so this change is _mostly_ just dropping in a new set of server-specific source files alongside the client-specific ones I created recently. The remaining changes in the shared SSH code are numerous, but all minor: - a few extra parameters to BPP and PPL constructors (e.g. 'are you in server mode?'), and pass both sets of SSH-1 protocol flags from the login to the connection layer - in server mode, unconditionally send our version string _before_ waiting for the remote one - a new hook in the SSH-1 BPP to handle enabling compression in server mode, where the message exchange works the other way round - new code in the SSH-2 BPP to do _deferred_ compression the other way round (the non-deferred version is still nicely symmetric) - in the SSH-2 transport layer, some adjustments to do key derivation either way round (swapping round the identifying letters in the various hash preimages, and making sure to list the KEXINITs in the right order) - also in the SSH-2 transport layer, an if statement that controls whether we send SERVICE_REQUEST and wait for SERVICE_ACCEPT, or vice versa - new ConnectionLayer methods for opening outgoing channels for X and agent forwardings - new functions in portfwd.c to establish listening sockets suitable for remote-to-local port forwarding (i.e. not under the direction of a Conf the way it's done on the client side).
2018-10-21 00:09:54 +03:00
{
Replace assert(false) with an unreachable() macro. Taking a leaf out of the LLVM code base: this macro still includes an assert(false) so that the message will show up in a typical build, but it follows it up with a call to a function explicitly marked as no- return. So this ought to do a better job of convincing compilers that once a code path hits this function it _really doesn't_ have to still faff about with making up a bogus return value or filling in a variable that 'might be used uninitialised' in the following code that won't be reached anyway. I've gone through the existing code looking for the assert(false) / assert(0) idiom and replaced all the ones I found with the new macro, which also meant I could remove a few pointless return statements and variable initialisations that I'd already had to put in to placate compiler front ends.
2019-01-03 11:12:19 +03:00
unreachable("Should never be called in the server");
Add an actual SSH server program. This server is NOT SECURE! If anyone is reading this commit message, DO NOT DEPLOY IT IN A HOSTILE-FACING ENVIRONMENT! Its purpose is to speak the server end of everything PuTTY speaks on the client side, so that I can test that I haven't broken PuTTY when I reorganise its code, even things like RSA key exchange or chained auth methods which it's hard to find a server that speaks at all. (For this reason, it's declared with [UT] in the Recipe file, so that it falls into the same category as programs like testbn, which won't be installed by 'make install'.) Working title is 'Uppity', partly for 'Universal PuTTY Protocol Interaction Test Yoke', but mostly because it looks quite like the word 'PuTTY' with part of it reversed. (Apparently 'test yoke' is a very rarely used term meaning something not altogether unlike 'test harness', which is a bit of a stretch, but it'll do.) It doesn't actually _support_ everything I want yet. At the moment, it's a proof of concept only. But it has most of the machinery present, and the parts it's missing - such as chained auth methods - should be easy enough to add because I've built in the required flexibility, in the form of an AuthPolicy object which can request them if it wants to. However, the current AuthPolicy object is entirely trivial, and will let in any user with the password "weasel". (Another way in which this is not a production-ready server is that it also has no interaction with the OS's authentication system. In particular, it will not only let in any user with the same password, but it won't even change uid - it will open shells and forwardings under whatever user id you started it up as.) Currently, the program can only speak the SSH protocol on its standard I/O channels (using the new FdSocket facility), so if you want it to listen on a network port, you'll have to run it from some kind of separate listening program similar to inetd. For my own tests, I'm not even doing that: I'm just having PuTTY spawn it as a local proxy process, which also conveniently eliminates the risk of anyone hostile connecting to it. The bulk of the actual code reorganisation is already done by previous commits, so this change is _mostly_ just dropping in a new set of server-specific source files alongside the client-specific ones I created recently. The remaining changes in the shared SSH code are numerous, but all minor: - a few extra parameters to BPP and PPL constructors (e.g. 'are you in server mode?'), and pass both sets of SSH-1 protocol flags from the login to the connection layer - in server mode, unconditionally send our version string _before_ waiting for the remote one - a new hook in the SSH-1 BPP to handle enabling compression in server mode, where the message exchange works the other way round - new code in the SSH-2 BPP to do _deferred_ compression the other way round (the non-deferred version is still nicely symmetric) - in the SSH-2 transport layer, some adjustments to do key derivation either way round (swapping round the identifying letters in the various hash preimages, and making sure to list the KEXINITs in the right order) - also in the SSH-2 transport layer, an if statement that controls whether we send SERVICE_REQUEST and wait for SERVICE_ACCEPT, or vice versa - new ConnectionLayer methods for opening outgoing channels for X and agent forwardings - new functions in portfwd.c to establish listening sockets suitable for remote-to-local port forwarding (i.e. not under the direction of a Conf the way it's done on the client side).
2018-10-21 00:09:54 +03:00
}
Convert a lot of 'int' variables to 'bool'. My normal habit these days, in new code, is to treat int and bool as _almost_ completely separate types. I'm still willing to use C's implicit test for zero on an integer (e.g. 'if (!blob.len)' is fine, no need to spell it out as blob.len != 0), but generally, if a variable is going to be conceptually a boolean, I like to declare it bool and assign to it using 'true' or 'false' rather than 0 or 1. PuTTY is an exception, because it predates the C99 bool, and I've stuck to its existing coding style even when adding new code to it. But it's been annoying me more and more, so now that I've decided C99 bool is an acceptable thing to require from our toolchain in the first place, here's a quite thorough trawl through the source doing 'boolification'. Many variables and function parameters are now typed as bool rather than int; many assignments of 0 or 1 to those variables are now spelled 'true' or 'false'. I managed this thorough conversion with the help of a custom clang plugin that I wrote to trawl the AST and apply heuristics to point out where things might want changing. So I've even managed to do a decent job on parts of the code I haven't looked at in years! To make the plugin's work easier, I pushed platform front ends generally in the direction of using standard 'bool' in preference to platform-specific boolean types like Windows BOOL or GTK's gboolean; I've left the platform booleans in places they _have_ to be for the platform APIs to work right, but variables only used by my own code have been converted wherever I found them. In a few places there are int values that look very like booleans in _most_ of the places they're used, but have a rarely-used third value, or a distinction between different nonzero values that most users don't care about. In these cases, I've _removed_ uses of 'true' and 'false' for the return values, to emphasise that there's something more subtle going on than a simple boolean answer: - the 'multisel' field in dialog.h's list box structure, for which the GTK front end in particular recognises a difference between 1 and 2 but nearly everything else treats as boolean - the 'urgent' parameter to plug_receive, where 1 vs 2 tells you something about the specific location of the urgent pointer, but most clients only care about 0 vs 'something nonzero' - the return value of wc_match, where -1 indicates a syntax error in the wildcard. - the return values from SSH-1 RSA-key loading functions, which use -1 for 'wrong passphrase' and 0 for all other failures (so any caller which already knows it's not loading an _encrypted private_ key can treat them as boolean) - term->esc_query, and the 'query' parameter in toggle_mode in terminal.c, which _usually_ hold 0 for ESC[123h or 1 for ESC[?123h, but can also hold -1 for some other intervening character that we don't support. In a few places there's an integer that I haven't turned into a bool even though it really _can_ only take values 0 or 1 (and, as above, tried to make the call sites consistent in not calling those values true and false), on the grounds that I thought it would make it more confusing to imply that the 0 value was in some sense 'negative' or bad and the 1 positive or good: - the return value of plug_accepting uses the POSIXish convention of 0=success and nonzero=error; I think if I made it bool then I'd also want to reverse its sense, and that's a job for a separate piece of work. - the 'screen' parameter to lineptr() in terminal.c, where 0 and 1 represent the default and alternate screens. There's no obvious reason why one of those should be considered 'true' or 'positive' or 'success' - they're just indices - so I've left it as int. ssh_scp_recv had particularly confusing semantics for its previous int return value: its call sites used '<= 0' to check for error, but it never actually returned a negative number, just 0 or 1. Now the function and its call sites agree that it's a bool. In a couple of places I've renamed variables called 'ret', because I don't like that name any more - it's unclear whether it means the return value (in preparation) for the _containing_ function or the return value received from a subroutine call, and occasionally I've accidentally used the same variable for both and introduced a bug. So where one of those got in my way, I've renamed it to 'toret' or 'retd' (the latter short for 'returned') in line with my usual modern practice, but I haven't done a thorough job of finding all of them. Finally, one amusing side effect of doing this is that I've had to separate quite a few chained assignments. It used to be perfectly fine to write 'a = b = c = TRUE' when a,b,c were int and TRUE was just a the 'true' defined by stdbool.h, that idiom provokes a warning from gcc: 'suggest parentheses around assignment used as truth value'!
2018-11-02 22:23:19 +03:00
bool ssh2channel_send_serial_break(SshChannel *sc, bool want_reply, int length)
Add an actual SSH server program. This server is NOT SECURE! If anyone is reading this commit message, DO NOT DEPLOY IT IN A HOSTILE-FACING ENVIRONMENT! Its purpose is to speak the server end of everything PuTTY speaks on the client side, so that I can test that I haven't broken PuTTY when I reorganise its code, even things like RSA key exchange or chained auth methods which it's hard to find a server that speaks at all. (For this reason, it's declared with [UT] in the Recipe file, so that it falls into the same category as programs like testbn, which won't be installed by 'make install'.) Working title is 'Uppity', partly for 'Universal PuTTY Protocol Interaction Test Yoke', but mostly because it looks quite like the word 'PuTTY' with part of it reversed. (Apparently 'test yoke' is a very rarely used term meaning something not altogether unlike 'test harness', which is a bit of a stretch, but it'll do.) It doesn't actually _support_ everything I want yet. At the moment, it's a proof of concept only. But it has most of the machinery present, and the parts it's missing - such as chained auth methods - should be easy enough to add because I've built in the required flexibility, in the form of an AuthPolicy object which can request them if it wants to. However, the current AuthPolicy object is entirely trivial, and will let in any user with the password "weasel". (Another way in which this is not a production-ready server is that it also has no interaction with the OS's authentication system. In particular, it will not only let in any user with the same password, but it won't even change uid - it will open shells and forwardings under whatever user id you started it up as.) Currently, the program can only speak the SSH protocol on its standard I/O channels (using the new FdSocket facility), so if you want it to listen on a network port, you'll have to run it from some kind of separate listening program similar to inetd. For my own tests, I'm not even doing that: I'm just having PuTTY spawn it as a local proxy process, which also conveniently eliminates the risk of anyone hostile connecting to it. The bulk of the actual code reorganisation is already done by previous commits, so this change is _mostly_ just dropping in a new set of server-specific source files alongside the client-specific ones I created recently. The remaining changes in the shared SSH code are numerous, but all minor: - a few extra parameters to BPP and PPL constructors (e.g. 'are you in server mode?'), and pass both sets of SSH-1 protocol flags from the login to the connection layer - in server mode, unconditionally send our version string _before_ waiting for the remote one - a new hook in the SSH-1 BPP to handle enabling compression in server mode, where the message exchange works the other way round - new code in the SSH-2 BPP to do _deferred_ compression the other way round (the non-deferred version is still nicely symmetric) - in the SSH-2 transport layer, some adjustments to do key derivation either way round (swapping round the identifying letters in the various hash preimages, and making sure to list the KEXINITs in the right order) - also in the SSH-2 transport layer, an if statement that controls whether we send SERVICE_REQUEST and wait for SERVICE_ACCEPT, or vice versa - new ConnectionLayer methods for opening outgoing channels for X and agent forwardings - new functions in portfwd.c to establish listening sockets suitable for remote-to-local port forwarding (i.e. not under the direction of a Conf the way it's done on the client side).
2018-10-21 00:09:54 +03:00
{
Replace assert(false) with an unreachable() macro. Taking a leaf out of the LLVM code base: this macro still includes an assert(false) so that the message will show up in a typical build, but it follows it up with a call to a function explicitly marked as no- return. So this ought to do a better job of convincing compilers that once a code path hits this function it _really doesn't_ have to still faff about with making up a bogus return value or filling in a variable that 'might be used uninitialised' in the following code that won't be reached anyway. I've gone through the existing code looking for the assert(false) / assert(0) idiom and replaced all the ones I found with the new macro, which also meant I could remove a few pointless return statements and variable initialisations that I'd already had to put in to placate compiler front ends.
2019-01-03 11:12:19 +03:00
unreachable("Should never be called in the server");
Add an actual SSH server program. This server is NOT SECURE! If anyone is reading this commit message, DO NOT DEPLOY IT IN A HOSTILE-FACING ENVIRONMENT! Its purpose is to speak the server end of everything PuTTY speaks on the client side, so that I can test that I haven't broken PuTTY when I reorganise its code, even things like RSA key exchange or chained auth methods which it's hard to find a server that speaks at all. (For this reason, it's declared with [UT] in the Recipe file, so that it falls into the same category as programs like testbn, which won't be installed by 'make install'.) Working title is 'Uppity', partly for 'Universal PuTTY Protocol Interaction Test Yoke', but mostly because it looks quite like the word 'PuTTY' with part of it reversed. (Apparently 'test yoke' is a very rarely used term meaning something not altogether unlike 'test harness', which is a bit of a stretch, but it'll do.) It doesn't actually _support_ everything I want yet. At the moment, it's a proof of concept only. But it has most of the machinery present, and the parts it's missing - such as chained auth methods - should be easy enough to add because I've built in the required flexibility, in the form of an AuthPolicy object which can request them if it wants to. However, the current AuthPolicy object is entirely trivial, and will let in any user with the password "weasel". (Another way in which this is not a production-ready server is that it also has no interaction with the OS's authentication system. In particular, it will not only let in any user with the same password, but it won't even change uid - it will open shells and forwardings under whatever user id you started it up as.) Currently, the program can only speak the SSH protocol on its standard I/O channels (using the new FdSocket facility), so if you want it to listen on a network port, you'll have to run it from some kind of separate listening program similar to inetd. For my own tests, I'm not even doing that: I'm just having PuTTY spawn it as a local proxy process, which also conveniently eliminates the risk of anyone hostile connecting to it. The bulk of the actual code reorganisation is already done by previous commits, so this change is _mostly_ just dropping in a new set of server-specific source files alongside the client-specific ones I created recently. The remaining changes in the shared SSH code are numerous, but all minor: - a few extra parameters to BPP and PPL constructors (e.g. 'are you in server mode?'), and pass both sets of SSH-1 protocol flags from the login to the connection layer - in server mode, unconditionally send our version string _before_ waiting for the remote one - a new hook in the SSH-1 BPP to handle enabling compression in server mode, where the message exchange works the other way round - new code in the SSH-2 BPP to do _deferred_ compression the other way round (the non-deferred version is still nicely symmetric) - in the SSH-2 transport layer, some adjustments to do key derivation either way round (swapping round the identifying letters in the various hash preimages, and making sure to list the KEXINITs in the right order) - also in the SSH-2 transport layer, an if statement that controls whether we send SERVICE_REQUEST and wait for SERVICE_ACCEPT, or vice versa - new ConnectionLayer methods for opening outgoing channels for X and agent forwardings - new functions in portfwd.c to establish listening sockets suitable for remote-to-local port forwarding (i.e. not under the direction of a Conf the way it's done on the client side).
2018-10-21 00:09:54 +03:00
}
Convert a lot of 'int' variables to 'bool'. My normal habit these days, in new code, is to treat int and bool as _almost_ completely separate types. I'm still willing to use C's implicit test for zero on an integer (e.g. 'if (!blob.len)' is fine, no need to spell it out as blob.len != 0), but generally, if a variable is going to be conceptually a boolean, I like to declare it bool and assign to it using 'true' or 'false' rather than 0 or 1. PuTTY is an exception, because it predates the C99 bool, and I've stuck to its existing coding style even when adding new code to it. But it's been annoying me more and more, so now that I've decided C99 bool is an acceptable thing to require from our toolchain in the first place, here's a quite thorough trawl through the source doing 'boolification'. Many variables and function parameters are now typed as bool rather than int; many assignments of 0 or 1 to those variables are now spelled 'true' or 'false'. I managed this thorough conversion with the help of a custom clang plugin that I wrote to trawl the AST and apply heuristics to point out where things might want changing. So I've even managed to do a decent job on parts of the code I haven't looked at in years! To make the plugin's work easier, I pushed platform front ends generally in the direction of using standard 'bool' in preference to platform-specific boolean types like Windows BOOL or GTK's gboolean; I've left the platform booleans in places they _have_ to be for the platform APIs to work right, but variables only used by my own code have been converted wherever I found them. In a few places there are int values that look very like booleans in _most_ of the places they're used, but have a rarely-used third value, or a distinction between different nonzero values that most users don't care about. In these cases, I've _removed_ uses of 'true' and 'false' for the return values, to emphasise that there's something more subtle going on than a simple boolean answer: - the 'multisel' field in dialog.h's list box structure, for which the GTK front end in particular recognises a difference between 1 and 2 but nearly everything else treats as boolean - the 'urgent' parameter to plug_receive, where 1 vs 2 tells you something about the specific location of the urgent pointer, but most clients only care about 0 vs 'something nonzero' - the return value of wc_match, where -1 indicates a syntax error in the wildcard. - the return values from SSH-1 RSA-key loading functions, which use -1 for 'wrong passphrase' and 0 for all other failures (so any caller which already knows it's not loading an _encrypted private_ key can treat them as boolean) - term->esc_query, and the 'query' parameter in toggle_mode in terminal.c, which _usually_ hold 0 for ESC[123h or 1 for ESC[?123h, but can also hold -1 for some other intervening character that we don't support. In a few places there's an integer that I haven't turned into a bool even though it really _can_ only take values 0 or 1 (and, as above, tried to make the call sites consistent in not calling those values true and false), on the grounds that I thought it would make it more confusing to imply that the 0 value was in some sense 'negative' or bad and the 1 positive or good: - the return value of plug_accepting uses the POSIXish convention of 0=success and nonzero=error; I think if I made it bool then I'd also want to reverse its sense, and that's a job for a separate piece of work. - the 'screen' parameter to lineptr() in terminal.c, where 0 and 1 represent the default and alternate screens. There's no obvious reason why one of those should be considered 'true' or 'positive' or 'success' - they're just indices - so I've left it as int. ssh_scp_recv had particularly confusing semantics for its previous int return value: its call sites used '<= 0' to check for error, but it never actually returned a negative number, just 0 or 1. Now the function and its call sites agree that it's a bool. In a couple of places I've renamed variables called 'ret', because I don't like that name any more - it's unclear whether it means the return value (in preparation) for the _containing_ function or the return value received from a subroutine call, and occasionally I've accidentally used the same variable for both and introduced a bug. So where one of those got in my way, I've renamed it to 'toret' or 'retd' (the latter short for 'returned') in line with my usual modern practice, but I haven't done a thorough job of finding all of them. Finally, one amusing side effect of doing this is that I've had to separate quite a few chained assignments. It used to be perfectly fine to write 'a = b = c = TRUE' when a,b,c were int and TRUE was just a the 'true' defined by stdbool.h, that idiom provokes a warning from gcc: 'suggest parentheses around assignment used as truth value'!
2018-11-02 22:23:19 +03:00
bool ssh2channel_send_signal(
SshChannel *sc, bool want_reply, const char *signame)
Add an actual SSH server program. This server is NOT SECURE! If anyone is reading this commit message, DO NOT DEPLOY IT IN A HOSTILE-FACING ENVIRONMENT! Its purpose is to speak the server end of everything PuTTY speaks on the client side, so that I can test that I haven't broken PuTTY when I reorganise its code, even things like RSA key exchange or chained auth methods which it's hard to find a server that speaks at all. (For this reason, it's declared with [UT] in the Recipe file, so that it falls into the same category as programs like testbn, which won't be installed by 'make install'.) Working title is 'Uppity', partly for 'Universal PuTTY Protocol Interaction Test Yoke', but mostly because it looks quite like the word 'PuTTY' with part of it reversed. (Apparently 'test yoke' is a very rarely used term meaning something not altogether unlike 'test harness', which is a bit of a stretch, but it'll do.) It doesn't actually _support_ everything I want yet. At the moment, it's a proof of concept only. But it has most of the machinery present, and the parts it's missing - such as chained auth methods - should be easy enough to add because I've built in the required flexibility, in the form of an AuthPolicy object which can request them if it wants to. However, the current AuthPolicy object is entirely trivial, and will let in any user with the password "weasel". (Another way in which this is not a production-ready server is that it also has no interaction with the OS's authentication system. In particular, it will not only let in any user with the same password, but it won't even change uid - it will open shells and forwardings under whatever user id you started it up as.) Currently, the program can only speak the SSH protocol on its standard I/O channels (using the new FdSocket facility), so if you want it to listen on a network port, you'll have to run it from some kind of separate listening program similar to inetd. For my own tests, I'm not even doing that: I'm just having PuTTY spawn it as a local proxy process, which also conveniently eliminates the risk of anyone hostile connecting to it. The bulk of the actual code reorganisation is already done by previous commits, so this change is _mostly_ just dropping in a new set of server-specific source files alongside the client-specific ones I created recently. The remaining changes in the shared SSH code are numerous, but all minor: - a few extra parameters to BPP and PPL constructors (e.g. 'are you in server mode?'), and pass both sets of SSH-1 protocol flags from the login to the connection layer - in server mode, unconditionally send our version string _before_ waiting for the remote one - a new hook in the SSH-1 BPP to handle enabling compression in server mode, where the message exchange works the other way round - new code in the SSH-2 BPP to do _deferred_ compression the other way round (the non-deferred version is still nicely symmetric) - in the SSH-2 transport layer, some adjustments to do key derivation either way round (swapping round the identifying letters in the various hash preimages, and making sure to list the KEXINITs in the right order) - also in the SSH-2 transport layer, an if statement that controls whether we send SERVICE_REQUEST and wait for SERVICE_ACCEPT, or vice versa - new ConnectionLayer methods for opening outgoing channels for X and agent forwardings - new functions in portfwd.c to establish listening sockets suitable for remote-to-local port forwarding (i.e. not under the direction of a Conf the way it's done on the client side).
2018-10-21 00:09:54 +03:00
{
Replace assert(false) with an unreachable() macro. Taking a leaf out of the LLVM code base: this macro still includes an assert(false) so that the message will show up in a typical build, but it follows it up with a call to a function explicitly marked as no- return. So this ought to do a better job of convincing compilers that once a code path hits this function it _really doesn't_ have to still faff about with making up a bogus return value or filling in a variable that 'might be used uninitialised' in the following code that won't be reached anyway. I've gone through the existing code looking for the assert(false) / assert(0) idiom and replaced all the ones I found with the new macro, which also meant I could remove a few pointless return statements and variable initialisations that I'd already had to put in to placate compiler front ends.
2019-01-03 11:12:19 +03:00
unreachable("Should never be called in the server");
Add an actual SSH server program. This server is NOT SECURE! If anyone is reading this commit message, DO NOT DEPLOY IT IN A HOSTILE-FACING ENVIRONMENT! Its purpose is to speak the server end of everything PuTTY speaks on the client side, so that I can test that I haven't broken PuTTY when I reorganise its code, even things like RSA key exchange or chained auth methods which it's hard to find a server that speaks at all. (For this reason, it's declared with [UT] in the Recipe file, so that it falls into the same category as programs like testbn, which won't be installed by 'make install'.) Working title is 'Uppity', partly for 'Universal PuTTY Protocol Interaction Test Yoke', but mostly because it looks quite like the word 'PuTTY' with part of it reversed. (Apparently 'test yoke' is a very rarely used term meaning something not altogether unlike 'test harness', which is a bit of a stretch, but it'll do.) It doesn't actually _support_ everything I want yet. At the moment, it's a proof of concept only. But it has most of the machinery present, and the parts it's missing - such as chained auth methods - should be easy enough to add because I've built in the required flexibility, in the form of an AuthPolicy object which can request them if it wants to. However, the current AuthPolicy object is entirely trivial, and will let in any user with the password "weasel". (Another way in which this is not a production-ready server is that it also has no interaction with the OS's authentication system. In particular, it will not only let in any user with the same password, but it won't even change uid - it will open shells and forwardings under whatever user id you started it up as.) Currently, the program can only speak the SSH protocol on its standard I/O channels (using the new FdSocket facility), so if you want it to listen on a network port, you'll have to run it from some kind of separate listening program similar to inetd. For my own tests, I'm not even doing that: I'm just having PuTTY spawn it as a local proxy process, which also conveniently eliminates the risk of anyone hostile connecting to it. The bulk of the actual code reorganisation is already done by previous commits, so this change is _mostly_ just dropping in a new set of server-specific source files alongside the client-specific ones I created recently. The remaining changes in the shared SSH code are numerous, but all minor: - a few extra parameters to BPP and PPL constructors (e.g. 'are you in server mode?'), and pass both sets of SSH-1 protocol flags from the login to the connection layer - in server mode, unconditionally send our version string _before_ waiting for the remote one - a new hook in the SSH-1 BPP to handle enabling compression in server mode, where the message exchange works the other way round - new code in the SSH-2 BPP to do _deferred_ compression the other way round (the non-deferred version is still nicely symmetric) - in the SSH-2 transport layer, some adjustments to do key derivation either way round (swapping round the identifying letters in the various hash preimages, and making sure to list the KEXINITs in the right order) - also in the SSH-2 transport layer, an if statement that controls whether we send SERVICE_REQUEST and wait for SERVICE_ACCEPT, or vice versa - new ConnectionLayer methods for opening outgoing channels for X and agent forwardings - new functions in portfwd.c to establish listening sockets suitable for remote-to-local port forwarding (i.e. not under the direction of a Conf the way it's done on the client side).
2018-10-21 00:09:54 +03:00
}
void ssh2channel_send_terminal_size_change(SshChannel *sc, int w, int h)
{
Replace assert(false) with an unreachable() macro. Taking a leaf out of the LLVM code base: this macro still includes an assert(false) so that the message will show up in a typical build, but it follows it up with a call to a function explicitly marked as no- return. So this ought to do a better job of convincing compilers that once a code path hits this function it _really doesn't_ have to still faff about with making up a bogus return value or filling in a variable that 'might be used uninitialised' in the following code that won't be reached anyway. I've gone through the existing code looking for the assert(false) / assert(0) idiom and replaced all the ones I found with the new macro, which also meant I could remove a few pointless return statements and variable initialisations that I'd already had to put in to placate compiler front ends.
2019-01-03 11:12:19 +03:00
unreachable("Should never be called in the server");
Add an actual SSH server program. This server is NOT SECURE! If anyone is reading this commit message, DO NOT DEPLOY IT IN A HOSTILE-FACING ENVIRONMENT! Its purpose is to speak the server end of everything PuTTY speaks on the client side, so that I can test that I haven't broken PuTTY when I reorganise its code, even things like RSA key exchange or chained auth methods which it's hard to find a server that speaks at all. (For this reason, it's declared with [UT] in the Recipe file, so that it falls into the same category as programs like testbn, which won't be installed by 'make install'.) Working title is 'Uppity', partly for 'Universal PuTTY Protocol Interaction Test Yoke', but mostly because it looks quite like the word 'PuTTY' with part of it reversed. (Apparently 'test yoke' is a very rarely used term meaning something not altogether unlike 'test harness', which is a bit of a stretch, but it'll do.) It doesn't actually _support_ everything I want yet. At the moment, it's a proof of concept only. But it has most of the machinery present, and the parts it's missing - such as chained auth methods - should be easy enough to add because I've built in the required flexibility, in the form of an AuthPolicy object which can request them if it wants to. However, the current AuthPolicy object is entirely trivial, and will let in any user with the password "weasel". (Another way in which this is not a production-ready server is that it also has no interaction with the OS's authentication system. In particular, it will not only let in any user with the same password, but it won't even change uid - it will open shells and forwardings under whatever user id you started it up as.) Currently, the program can only speak the SSH protocol on its standard I/O channels (using the new FdSocket facility), so if you want it to listen on a network port, you'll have to run it from some kind of separate listening program similar to inetd. For my own tests, I'm not even doing that: I'm just having PuTTY spawn it as a local proxy process, which also conveniently eliminates the risk of anyone hostile connecting to it. The bulk of the actual code reorganisation is already done by previous commits, so this change is _mostly_ just dropping in a new set of server-specific source files alongside the client-specific ones I created recently. The remaining changes in the shared SSH code are numerous, but all minor: - a few extra parameters to BPP and PPL constructors (e.g. 'are you in server mode?'), and pass both sets of SSH-1 protocol flags from the login to the connection layer - in server mode, unconditionally send our version string _before_ waiting for the remote one - a new hook in the SSH-1 BPP to handle enabling compression in server mode, where the message exchange works the other way round - new code in the SSH-2 BPP to do _deferred_ compression the other way round (the non-deferred version is still nicely symmetric) - in the SSH-2 transport layer, some adjustments to do key derivation either way round (swapping round the identifying letters in the various hash preimages, and making sure to list the KEXINITs in the right order) - also in the SSH-2 transport layer, an if statement that controls whether we send SERVICE_REQUEST and wait for SERVICE_ACCEPT, or vice versa - new ConnectionLayer methods for opening outgoing channels for X and agent forwardings - new functions in portfwd.c to establish listening sockets suitable for remote-to-local port forwarding (i.e. not under the direction of a Conf the way it's done on the client side).
2018-10-21 00:09:54 +03:00
}
Add an interactive anti-spoofing prompt in Plink. At the point when we change over the seat's trust status to untrusted for the last time, to finish authentication, Plink will now present a final interactive prompt saying 'Press Return to begin session'. This is a hint that anything after that that resembles an auth prompt should be treated with suspicion, because _PuTTY_ thinks it's finished authenticating. This is of course an annoying inconvenience for interactive users, so I've tried to reduce its impact as much as I can. It doesn't happen in GUI PuTTY at all (because the trust sigil system is used instead); it doesn't happen if you use plink -batch (because then the user already knows that they _never_ expect an interactive prompt); and it doesn't happen if Plink's standard input is being redirected from anywhere other than the terminal / console (because then it would be pointless for the server to try to scam passphrases out of the user anyway, since the user isn't in a position to enter one in response to a spoof prompt). So it should only happen to people who are using Plink in a terminal for interactive login purposes, and that's not _really_ what I ever intended Plink to be used for (which is why it's never had any out-of-band control UI like OpenSSH's ~ system). If anyone _still_ doesn't like this new prompt, it can also be turned off using the new -no-antispoof flag, if the user is willing to knowingly assume the risk.
2019-03-10 17:42:33 +03:00
bool ssh2_connection_need_antispoof_prompt(struct ssh2_connection_state *s)
{
return false;
}